The question would also extend to Britain if it were ever conquered. These countries were considered Aryan (as far as I'm aware) so the Nazis would have certainly had different plans for Western (maybe southern?) European nations, what were they?
Was it formal annexation into Germany, like Austria or the Sudetenland? When was the occupation supposed to end?
Hello, I am clearly not a specialist of this particular period but I have made just made some research to verify that what I have read some years ago is indeed true. You probably know that there are germans living in the Trentino regions claimed and annexed by Italy in 1918. Because of the germano-italian alliance the nazis couldn't reclaim those territories so they had to find another way to integrate those germans into the Reich. Their solution was to annex the french region of Franche-Compté, rename Besançon Bolzen so it would look like Bolzano/Bozen force the french to move elsewhere and settle the territory with those tyrolians. They were around five time less than the population of Franche-Comté, but a strong natality rate was supposed to repopulate the territory in a few generations. But this project "Burgund" had the problem to seriously cripple the possibilities of a reconciliation with France, so it was at least postponed, they also considered to send the Tyrolians in Crimea, with speculation of a gothic population of Crimea that took refuge in Tyrol (one of the many speculations of the nazi history of migrations).
Source (in french)
Yeah I believe it's been asked before a few times but in short what you're asking about is the Greater Germanic Reich, a single sovereign state stretching from the Rhine to the Urals. I don't have any scholarly sources on it at the moment but I heard it's made mention of in Mein Kampf which is about as primary of a source as it gets.
The idea was to incorporate them into "ein Reich" as far as a state (federation) goes, though the party could not reach a single agreement on the ideological value of "Germanic" vs "German." Apparently, however, pan-Germanic colonists of all nations were good enough to be sent to the conquered east. The term Aryan was also mostly used to distinguish the master race ideology, but Hitler's actual racial views were a bit more in depth, but I digress.
It would technically be annexation or "Anschluss" but not on the level of Austria, Sudetenland, or the other - provinces - seen as lost from Germany in the first place. I don't know about specific occupation durations but I imagine it would be dependent on the spread of the ideology which was relatively rapid (I recently read an article about it in the Netherlands which the article deemed significant because it regarded the nation as one of the most liberal and welcoming nations in Europe).
The plan specifically for the British Empire was to maintain it as a seafaring and global relations parter (with the Greater Germanic Reich) which would retain its own sovereignty entirely. However, you asked if Britain were conquered (which Hitler did not want to do because the empire would be lost and the allies would likely absorb or recognize the independence of various dependencies and such). A conquest would most likely result in a gradual process granting autonomy with added Germanization.
The alliance with Italy and Hitler's personal admiration for Mussolini led the support for Italy's new "Roman Empire" (with Italian being a relatively new construct no doubt in part thanks to Mussolini) with north east Africa primarily.
Some nations in Europe such as Switzerland and Finland were to be untouched. Essentially, however, their dream was for the British Empire across the seas to the west, the Italian Empire as the underbelly to the south, and the Japanese Empire (seen as honorary aryans for their ultranationslism and similar position in Asia) to the far east, with the Greater Germanic Reich as the center of it all.
I am not a historian, just a lover of all kinds of history, and I don't believe we should shy away from the darker parts. Take this for what you will, and I will try to go back and look for sources once I get time. Hopefully that answered your question. :)
EDIT: Here are some interesting articles on it. I haven't found the article on the Netherlands.
From Illusion to Destruction: The Germanic Bid for World Power, 1897-1945 Michael D. Biddiss British Journal of International Studies Vol. 2, No. 2 (Jul., 1976) , pp. 173-185 Published by: Cambridge University Press Stable URL: http://www.jstor.org/stable/20096770
Hitler and Germanentum Bernard Mees Journal of Contemporary History Vol. 39, No. 2, Understanding Nazi Germany (Apr., 2004) , pp. 255-270 Published by: Sage Publications, Ltd. Stable URL: http://www.jstor.org/stable/3180724
The FAQ has some threads about this already:
http://www.reddit.com/r/AskHistorians/wiki/wwii#wiki_axis_alliance_and_post-war_plans