Oh, these are phenomenal questions! I'm abroad right now or else I would give a more thorough answer (no books, no computer,little internet etc.), but I'll post some sources and some brief explanations. Sorry I'm on mobile so I just included the full links to some pictures.

1. Before becoming the showman we know today, William F. Cody worked as a scout for the U.S. Army. Cody initially began his army career in 1863 (at the age of 17), and later became a full time scout in 1868 until he left the post in the early 1870s. He participated in the heighth the buffalo hunt from 1871 to 1873 in Kansas, where scenes like this: (http://www.google.com/imgres?imgurl=http://cache.wists.com/thumbnails/7/37/7377f4d1d8add3298c08c9d8cff15046-orig&imgrefurl=http://www.oobject.com/most-interesting-scrap-yards/buffalo-skull-mountain/7066/&h=392&w=500&tbnid=tunua-GDxH58fM:&docid=OigLuin8axFyfM&hl=en&ei=IPjJVYyjI4mwyQTunYDYAg&tbm=isch&client=safari&ved=0CB0QMygAMABqFQoTCIyz_ were common. By 1878 the great southern herd of buffalo was gone and by 1883 buffalo disappeared from the northern plains as well. These hunts were an absolute tragedy. Monstrous herds that had supported tribes for hundreds of years ( perhaps thousands? Is there an Anthropologist in the room?) disappeared in little more than a decade. The effect on plains tribes was devastating (see #4). Their meat was used to satisfy temporary railroad and army interests. Some scholars, like Richard White in his book Railroaded, argue that the transcontinentals were an unnecessary imperial venture... See the Depression of 1893 for more. I can't remember the exact figures, but the sale of buffalo hides and meat brought the railroad very little wealth or traffic for the trains (these figures are included in Railroaded and I think I wrote about them in a past post). Cody participated in the hunt, but he did not play any key role in the sale and transport of the dead buffalo. Cody was an adept scout who leveraged his position as a scout and his looks (http://www.google.com/imgres?imgurl=https://upload.wikimedia.org/wikipedia/commons/8/86/Buffalo_Bill_Cody_by_Sarony,_c1880.jpg&imgrefurl=https://en.wikipedia.org/wiki/Buffalo_Bill&h=2157&w=1465&tbnid=5QFd9tC8VkM_CM:&docid=SrnUuALEyGRVoM&hl=en&ei=HADKVaGgBMOiyAT2x7DQAg&tbm=isch&client=safari&ved=0CCUQMygIMAhqFQoTCKGescGYoccCFUMRkgod9iMMKg) to start performing in small theatrical productions where he reenacted different western scenes for an eastern audience. Easterners were enthralled by the 'mystery' of the West and sought to see images of Indians before they vanished (contemporary anthropologists and ethnologists believed Indians were soon to disappear). Cody saw opportunity in this fascination and played about eastern imaginations to start a new career as a showman. He slowly built up his reputation as an authentic western character (having seen the last of the buffalo) and used his personal charisma to sell this image, thus creating "Buffalo Bill". It was only a little bit later that he began touring with his own show with his partner (I'm blanking on the name).

2. I have never read or heard anything about Cody regretting the loss of the buffalo or later calling for conservation. From the time he began the Wild West show until his death Buffalo Bill never left the stage (he had to make a living and the show was not always successful). He worked up until his death in the business, even finishing a film set in the west before he died, of which only a few fragments exist today. So I would ask the counter question: why does it even matter? The buffalo were gone, there were no significant attempts repay Native people and Cody continued on as a celebrity.

3. This is a very complex question and people have written entire books on the subject (see the sources below). I think the answer is twofold. The shows clearly improved the public's opinion of native people, who were often simply seen as a 'savage' other, an evil enemy who threatened American expansion and safety. The presence of real natives in the show softened this perception. Sitting Bull himself appeared for some years in the show and he was said to have had quite an affect on audiences. However, Buffalo Bill's show stereotyped Indians with different plays like the favored "Custer's Last Stand." This created enduring stereotypes for the majority of Americans that still hold root today (headdress, moccasins, war whoops, etc). Buffalo Bill opened the door for the Western film genre and other Western celebrities like Wild Bill and Kit Carson. Cody was largely responsible for the early creation of mythological American ideas of a "Wild West." One of the most interesting parts of the Wild West show is the performers themselves. Native actors were able to use their position in the show to travel around the world, gain new public voice, improve their financial standing, and acquire powers that might have otherwise eluded them. I would read some of the titles I included below for more information on this or look at the writings of Luther Standing Bear (these diaries are probably online), who was Sitting Bull's right hand man.

4. A good example would be the Blackfeet of the northern plains. They once roamed all over Montana and Canada, but after the loss of the buffalo they were relegated to a small reservation in the northern Rockies. The first great trial they faced was disease, which devastated their tribe before contact with Europeans, as it did with other Native peoples. The Blackfeet had few military encounters with the United States (they are a farflung tribe relative to other famous ones who fought directly like the Sioux) and their will was largely broken during the Baker Massacre, where some 200 members (men, women, children) of the tribe were mistakenly killed by the U.S. Calvary (This sparked a major backlash by the U.S. Public during Grant's presidency). I find this to be one of the saddest moments in U.S. History. During the "starvation winter" of 1883 (no buffalo), the already weakened Blackfeet saw a quarter of their population die from malnutrition, disease and the cold... And this is only one of the many hard winters faced by the tribe. Later, at the end of the 1800s the tribe had to sell their mountains (many of which were sacred) to the U.S. Government, merely to get funds to buy supplies in order to survive (and by the way, they got shafted on the price, they hardly would have gotten anything without help from conservationists like George Grinell). War, Disease, Famine, broken treaties, lost lands, corrupt officials were all issues that affected Native Peoples. You really have to look at the history of each tribe individually to see what was the most devastating in different areas. Here I'm drawing from William E. Farr's The Reservation Blackfeet and I would say the best book on the subject is Joy S. Kasson's Buffalo Bill's Wild West. I would also check out Wild West Shows and the Images of Native Americans by L.G. Moses. Another interesting title for this subject would be Playing Indian by Phillip Deloria. Also, everyone in The U.S. should watch Buffalo Bill's Wild West, or Sitting Bull's History Lesson by Robert Altman. It stars Paul Newman as Buffalo Bill and is one of my all time favorite films.

[PART 1]

Excellent questions, all! And I too was very intrigued by Ms. Rousey's IAMA answer re: Buffalo Bill. Here's why...

So, first off: William "Buffalo Bill" Cody killed his fair share of buffalo, yes. Not any more than a lot of other men who worked the plains in the 1860s & 70s (Wyatt Earp killed his fair share as well, for example), but enough to fairly be called a buffalo killer. To call the man some kind focal point for the very-near extermination of the buffalo in North America, and by reasonable extension, the decline of Native American culture and society in the Great Plains region, would be a stretch, however. The man didn't organize the efforts to eliminate the buffalo in that region; he, like many men of that time and place, simply took advantage of a booming industry. In any event, like the OP mentioned, his nickname didn't really come from being a prolific or notable buffalo killer, but rather from a specific incident pertaining to Bill's work with the railroad. This hardly excuses the shameful history of the decline of the buffalo in North America, or the way that was used to take yet another important component of Native American culture away from those people, but it gives some context to Bill as a historical figure, at least.

NOW...with that out of the way, let it be honestly said that Buffalo Bill Cody was a HUGE figure in the formation of the myth of "The West" as we know it today. Further, the fact that even today, Ronda Rousey is perpetuating this myth that Buffalo Bill played a big part in the formation (and by modern perspectives, destruction of) "The West" shows you how intense this shared understanding is.

Why, and in what way?

Well I'm glad you asked. In the mid-19th century, there were these things called Dime Novels. They were the comic books of the day, yet instead of superheroes with powers and mutant abilities, they were about the daring characters that lived out "West." Although the dynamics of the characters and the stories changed over time, they all pushed a fairly common theme: the "West" was a dangerous place, and the heroes of the stories were those who fought back against the wicked villains, and restored (or brought) order to the chaos. There were a lot of ethnic and gender components involved; Mexicans, Jews, and especially Native Americans were the villains, while women were included only to be saved by the white hero (I know, I know...ridiculous, but that's almost always how they were written). These Dime Novels made up fictional characters at times, but were always eager to use real life figures to punch up their narratives, and excite readers who were already familiar with a popular folk hero of sorts. Kit Carson was a big figure in the Dime Novels (hell, even Jesse James for a time), but Buffalo Bill was maybe the most popular.

Buffalo Bill had been a popular figure in Dime Novels in the late 1860s and early 1870s based on his frontiersman reputation, but after his Wild West tour got popular, his Dime Novel dynamic changed. His Wild West tour (he hated it when people called it a "show" since he considered it legit in its presentations) was a travelling circus of sorts that had stage monologues, trick shot demonstrations, and the battle recreations and re-tellings that used real Native Americans and frontier cowboys... [cont]

It's been some time since I read it and your question is so detailed and well-written that I am intimidated to only partially answer it but I thought I would chime in and strongly recommend Steve Rinella's American Buffalo: In Search of a Lost Icon. It's a beautifully written book not just about the history of the buffalo, but the modern conservation efforts, interwoven with the story of an expert hunter who won a lottery to hunt one in Alaska.

Additional question: In Canada (or maybe just according to my misinformed spcial studies teacher) we were taught Buffalo Bill and other hunters were hired by the US government to kill buffalo in large numbers, with the explicit purpose of starving out Plains Natives. Did the US or Canada actually have any programs that encouraged this? Were they that explicit in their objective?

I have performed a living history act as Buffalo Bill Cody for several years, portraying the famous bullwhacker, hunter, scout, actor and showman for museums, libraries, retirement homes, scout troops and schools. Like a lot of American heroes of the 19th century, Cody stretched the truth. Cody was hired in 1868 to provide meat for the men building the railroad through Kansas. The eventual completion of the railroad allowed the stockyards and slaughterhouses that were being built in Chicago to prosper and provide meat across the country. Until then, meat was obtained locally by hunting it for oneself or visiting local market hunters who provided meat. Cody was hired by a contractor for the railroad to provide the meat of twelve buffalo a day. He set out each morning on his buffalo hunting horse Brigham, with a butcher named Scottie, a buckboard and a couple of mules to locate a herd and kill twelve or fourteen buffalo. Scottie would rip the hide off. They would take the rump, the hump and the tongue, the most edible meat, load it on the buckboard and take it back to iron's end where the railroad men would sing, Buffalo Bill, Buffalo Bill, Never missed and never will. Always aims and shoots to kill, And the company pays his buffalo bill.

That's where he got his name of Buffalo Bill. Cody calculated that he killed 4,280 buffalo for the railroad and all for meat. When Lewis and Clark traveled through the Louisiana Purchase they calculated there were up to 60,000,000 buffalo on the plains. The four and half thousand Cody killed did little to affect that number.

During the 1860s when Cody was shooting buffalo in any great numbers the only way to tan a hide was to have someone stake it down and brain tan it with the brains of two or three buffalo. The Bison Bison is the only animal without enough brains to preserve its own hide. The hides, unless treated in this manner were worthless, ending up as flint hard hides of little use.

In 1870 there was a shortage of chrome-tanned cowhide due to a Rinderpest epidemic and the tanneries in Europe sought a replacement for this most popular material for flat drive belts of the Industrial age. The demand for drive belts led to tanneries in England and Germany developing a method to tan those flint hard dried hides. The resulting leather was thicker, more supple, more resistant to wear, and available in larger lengths than chrome-tanned cowhide and buffalo hide became the preferred material for the flat drive belts of the industrial age. At that point the demand caused the price of a buffalo hide to climb to close to $3.00 each. There were many men in America left unemployed, but armed, by the end of the War of Rebellion and it was possible to take to the frontier and earn hundreds of dollars a day. According to David A. Dary in "The Buffalo Book" on page 73, "During the 1820s...the trade in buffalo robes and buffalo tongues began to increase, and during the early 1820s about 200,000 buffalo were killed annually on the plains. But only about 5,000 of these were killed by white men." Tongues were prized by the Native American tribes and as I mentioned the tanning of robes was a manual and time-consuming process at that time. In "Buffalo Nation (Wildlife) by Valerius Geist, he explains that by the 1880s the tanneries were processing hundreds of thousands of hides each year into the new type of leather. In 1885, the second year that Cody toured the Wild West he became aware of the serious reduction in the herd on the plains. A major part of his show was the small herd of buffalo that traveled with him. He was friends with Pawnee Bill, a fellow showman who also had a small herd of buffalo on his ranch in Oklahoma. Cody was also friends with a man named Charles Jesse "Buffalo" Jones a fellow frontiersman and rancher. In the spring of 1886 Buffalo Jones set out from his ranch in Kansas toward the Texas Panhandle to locate remaining buffalo. He lassoed eighteen calves and took them back to his ranch. Together these three men helped to preserve a herd that became the basis of the herd in Yellowstone National Park today. Here is a photo of the three men. https://www.facebook.com/buffalobillinsong/photos/pb.203714502975030.-2207520000.1439307346./762290990450709/?type=3&theater

Cody's buffalo hunting contest on the prairie was with William Averill "Medicine Bill" Comstock, during which Comstock killed 46 buffalo and Cody killed 69 to win the $500 prize and title of Champion Buffalo Hunter. There is some controversy over whether this contest actually happened. Some historians believe it did, and point to some old beer and champagne bottles supposedly found in the area the hunt was supposed to take place in. By the time Cody wrote about it in his autobiography he was the only one left alive. Comstock was killed after visiting the camp of Cheyenne Chief Turkey Leg with his friend Abner "Sharp" Grover in 1868 just a few months after Cody said the contest took place. Comstock was called the "Ace of Scouts" by Sheridan and Custer and was the grand nephew of James Fenimore Cooper, author of the Leather Stocking Tales and grew up believing himself to be Natty Bumpo.

So, for your first two questions, although Cody was a famous buffalo hunter, he had stopped hunting and become an actor by the time of the greatest slaughter of the herds, and he actually did go into partnership with Pawnee Bill and Buffalo Jones to help preserve the buffalo. He may have done it for altruistic reasons, but it was in his own best interests to keep his namesake alive.

Finally, Cody was a friend of his former enemy. There is deep truth in this statement that he made when Sitting Bull was a member of the troupe. He began hiring Pawnee scouts he had met and befriended during his years as a civilian scout employed by the Army. His friend Major Frank North was a well-respected commander of the Pawnee scouts who was considered to be a honorary chief by the men he commanded. When Frank was injured and later died of his wounds in a riding accident during a performance of the Wild West, Cody lost his best Pawnee interpreter. He also had Lakota interpreters, John Young Nelson and Broncho Bill Irving so he began primarily hiring Lakota performers for his show.

In 1890, when Cody employed 65 Lakota performers in the Wild West, he toured the world with what at the time was the only remaining nomadic Lakota village. On the reservations Lakota were forbidden to speak Lakota, forbidden to dress as Lakota and were given spoiled provisions to eat. the only employment open to them was road building, ditch digging, lumbering or performing in the Wild West. In 1890, five Lakota performers were killed by accident in the arena or disease and caused a furor in America over the fates of the performers. According to Sam A. Maddra in "Hostiles? The Lakota Ghost Dance and Buffalo Bill's Wild West"... "In the year 1890, drought, the worst known for many years, afflicted the western part of South Dakota, and the Indian cropps were a total failure. There is ample evidence that, during this period, the rations issued lasted, even when carefully used, for only two-thirds the time for which they were intended. addedd to their distress, this period 1889 and 1890, was marked by extraordinary misfortune. The measles prevailed with great virulence in 1889, the grippe in 1890. Whooping cough also attacked the children. THe sick died from want...The people were often hungry, and, the physicians in many cases said, died when taken sick not so much from disease as for want of food." 25-45 died each month on the reservation. Also according to Sam A. Maddras in 1890 the total revenue for Pine Ridge was $32,000 and $28,000 of that came from the Lakota performers of the Wild West.

Most Americans in those days of the closing frontier only knew what they had heard or read about Native Americans, that they were savages and brutes. It was between performances of the Wild West that the crowds were able to tour the lot and see the tipis of the Lakota village where mothers took care of children, did the cleaning and carried on daily tasks like everyone.

During the Indian Attack on the Settler's Cabin, a popular skit during the performances, the settler's wife was portrayed by Ma Whittaker, the costume lady. The settler himself was John Young Nelson. One of the attacking Lakota was Nelson's son Yellow Horse Nelson and one of the rescuing cavalry was Sam Lone Bear, who often rode in cavalry uniform during rainy performances to protect his delicate buckskins and feathers. You can see films of the Lakota performers riding during a Wild West performance on YouTube and it may be the only time you see a Lakota smiling. They were having fun. Cody preferred they speak Lakota, dress Lakota, act Lakota and introduced each of them as Chief "so and so" to every Queen, Prince, Princess, Tycoon or Pope they met.

While touring the world, even South of the Mason Dixon Line, the performers of the Wild West ate from the same pots, under the same tent, Lakota, Arab, Georgian, Whie Cowboy, Black Cowboy, Mexican Vaquero, Argentine Gaucho, everyone, although he mentioned that each group liked to eat together and they had their own preferred condiments.

Cody also hire many women performers and always paid them the same as the men performers. He had famous cowgirls like Emma Lake Hickok and Lulu Belle Parr who did dangerous equestrian acts and he said he believed they deserved to be paid the same as men for the same job.

I'm sorry that I can really only answer the last part and not to the best of my abilities because I mainly focus on Canadian aboriginal people. But because nobody else has written anything I'll give some info. The metis in Canada had a culture that centered on the Buffalo hunt to the point where their self government and legal codes were based on rules for the hunt. With the decline in the Buffalo population they not only lost their primary source of income but a great deal of cultural foundation was lost also. Many aboriginal peoples in Canada view this kind of blow to their culture to be responsible for a lot of the decline in traditions and community.