Did the Japanese benefit from joining the allies in WWI?

Japan was an ally of the Entente powers from 1914 to 1918, so the whole of World War I. It helped greatly in securing the sea lanes of the South Pacific and the Indian Ocean. By doing this, it was fighting against the Kaiserliche Marine, the German Navy.
Personally, I think that Japan gained a lot from this. Firstly, Japan gained all of Germany's Pacific territory, the reason for which the Navy begun to receive double the investment of the government than the Army. After the Russo-Japanese war of 1904-5, that Japan won by a great margin (destroying nearly the entire Russian navy, Japan regained territories in China. The Japanese used WWI to increase its sphere of influence further. The victory of the Japanese in the Russo-Japanese war was the first time an Asiatic power had beaten a Western one and established Japan as a great power to a certain extent, however, WWI did so more.
However, the main point that I want to make about Russia benefitting from WWI was its joining of the council of the League of Nations after the Paris Treaties. This was mostly because the European powers needed a non-European one to make the League seem world-wide, however this officially made Japan a great power. Its place in the Council meant it could veto any decision and had a great power over world decisions. However, it also enabled it to invade Manchuria in 1931, as the League of Nations didn't pay attention to it until it was too late (main powers didn't want to lose Japan as an ally?). Nevertheless, the invasion of Manchuria did result in Japan leaving the League in 1933 (notice how long afterwards), with the words of Matsuoka: "We are not coming back".


Questions to consider:

1. To what extent did the successes of the Japanese Navy (military) in WWI lead to its military government two decades later?
2. Did the League actually have power anyways which Japan could therefore sway?
3. Was Japan still looked down upon slightly by the European powers?