Oh fun, Washington Naval Treaties.

I assume for the first few questions you are talking about the three main parties-the US, the UK, and Japan. As you probably know, the three main countries received tonnage restrictions roughly equivalent to 10/10/7. This meant that the US and UK would have similar size navies, and Japan would be 70% less. Japan was furious at this as it seemed to imply that Japan was less of a country than the UK and the US, especially so as this was the minimum the Japanese government was willing to accept (which was partly due to the US breaking Japanese codes).

The reasoning for this, however, was simple. Britain had a worldwide empire, and needed ships to protect its interests in the North Sea (Britain), the Mediterranean, and the Indian Ocean. Hence it was considered a "three sea navy." The US was a "two ocean navy" in the sense that it had to defend the Atlantic and the Pacific. Japan only had to defend the Pacific, so the argument was that Japan's fleet did not need to be as large.

It would thus seem that Japan was actually the major beneficiary of the treaty as a result. As Japan could concentrate its naval forces more than the other two powers, and as Japanese industries paled compared to US industrial power, this would initially seem to be an advantageous situation for Japan.

In actuality, this treaty's biggest winner was the United States. Not only had the US managed to play Britain and Japan against each other, permanently destroying any hopes of reviving the Anglo-Japanese alliance (and thereby removing the threat of a British-Japan dominated Asia), they also had the Panama Canal, which was under no threat from potential enemies (like Germany and Italy with regards to the Suez Canal) and allowed them to move ships from the Atlantic to the Pacific and vice versa. Also, the US had the largest industrial capacity, meaning that upon the renouncement of the Naval treaties the US was quickly able to outproduce existing fleets.

The British fleet was primarily in their surface vessels. Their submarine forces were a relatively minor portion of the fleet, primarily because they didn't need submarines. If anything, submarines were a major threat to their ships, to the point that they wanted to outright ban submarines, period.

The Japanese won a minor point by preventing the US and UK from building fortifications in the West Pacific. But it was relatively minor because supplying such forts would have been extremely difficult, as was seen with the fall of Singapore (which was extremely fortified) to Japan in early WWII. Ultimately it didn't matter much-Japan would have been able to cut off the fortresses and siege them into submission. It may have cost them some more time and ships-like at Wake Island-but it would have not affected the main forces of the war, which was US industrial might and poor Japanese decision making.

Most countries did not realize how important carriers were at this time. Battleships were still seen as the primary surface ship, especially by the Japanese, whose two primary carriers-Akagi and Kaga-were converted from a battlecruiser and battleship, respectively. The main concern with restricting carriers was to prevent countries from making large capital ships with a lot of guns. That's why carriers had the # of heavy guns on them restricted-not because they were carriers, but because they were large ships with the potential to be just as armed as battleships. Bear in mind that the carriers we imagine today are a more recent innovation that evolved from the Midway and Essex class carriers of mid-late WWII.

I can't really comment on how the conversions may have influenced decisionmakers specifically, but presumably for the US they had impressed Congress enough to allow for the commissioning of 12 new Essex-class carriers in 1940, well before Pearl Harbor. On the other hand, Japan had three carriers in construction as well (Shoukaku, Zuikaku, and Taiho) but 5 battleships (the Yamato class), signifying that their main focus was still on battleships, not carriers.

Aside from the fact that it would be obscenely difficult to hide a battleship under construction, all sides had military liaisons that would conduct reporting on each country to ensure they were following the agreed upon terms. In fact, there are likely some US intelligence reports on this matter in the National Archives.

As for your last question, the British Nelson class battleships were laid down in December 1922 and completed in 1925, although she was fully commissioned in 1927. So 3-5 years. However, the Colorado-class and the Japanese Nagato class took about 2 years to build and one additional year for trials prior to commissioning. Those were laid down in 1918-1920, however.

Let me answer part of you question the best I can. Germany was not included in the Washington Naval Treaty because restrictions on the size of their navy was already dictated by the Treaty of Versailles. The German Navy could only consist of a maximum of: Six pre-dreadnought battleships six light cruisers (not exceeding 6,000 long tons (6,100 t)) twelve destroyers (not exceeding 800 long tons (810 t)) twelve torpedo boats (not exceeding 200 long tons (200 t)) submarines forbidden (http://en.wikipedia.org/wiki/Treaty_of_Versailles#Military_restrictions)

As for Turkey, a separate treaty (Treaty of Sèvres) was draft to end Turkey's involvement in WWI. However, this treaty was never adopted and therefore never enforced. This treaty would have limited the size of Turkey's Navy to: seven sloops six torpedo boats

Treaty was never ratified because Turkey descended into Civil War following WWI and Treaty of Lausanne (1923) superseded the previous treaty. The Treaty of Lausanne was the final peace accord between the allies and Turkey.

As for Russia, when this treaty was being drafted it was still in the throws of a civil war. I mean the Soviet Union didn't even exist before 1922, therefore was in not position to agree to any treaties.