I saw several of those expansions in their bins during the play-test weekend. I would recommend contacting Mr. Friend about them. I know for a fact that they have some Croatia and a few Winter War. Didn’t really look into the others.
If you have a copy each of Europe '40 and Pacific '40, as well as a copy of 1914, you should have enough pieces to be able to pull it off. Personally, I use the British from 1914 for Chinese Nationalist pieces, and the Turks as Chinese Communists. You can use the 1914 Germans as Axis minors, and the French as Vichy.
On the old map there was an airbase on Guam.The new map, as mentioned features no bases. Thing is, there is no airbase for Guam in the 4.1 set-up. Will there be 5.0 set-up charts?