OK… I’ll grant all those qualifiers.
I just don;t see anyone lettingh you send 10-15 FIGs to Germany. Any serious attempt at that invites Island Hopping (and with judicious use of UK’s initial fleet, and with only modest US fleet build in US1, the US is a match fo Japan’s navy… to maintain superiority, Japan has to build navy, meaning no tech rolls and no FIGs to Germany…
Also, Japan is VERY weak on land units to start. You need a few turns (building IC’s as you stated) just to get Japan viable in Asia with land units. So your AF move is a mid-game strat to start with… then add in a few turns to execute…
You just usually are not going to ahve that time, even in a straight KGF.