I don’t know that Germany would be in much of a position to push you back with too much beyond planes.
As an Allied player, I would be happy to get pushed off again in the first or second attempt if it meant the German air force was being reduced.
The Mexican Naval Base still has some value no matter what Japan does. Because if they see it and decide not to attack in order to screw your plan, this only helps India and ANZAC prepare.
Actually, if Japan invades FIC, it only costs them the $10 NO for peaceful relations with the United States. It doesn’t bring the US into the war.
All those other things do however. Also, if any territory in North America gets taken by the Axis, US can declare war. Basically this means Canadian territories.
Retreating is done at the end of a combat round. You can’t skip the prior steps and go straight to retreating, so you must fight at least one round of each declared battle. It’s the same in all versions.
However, in AA42, AA50, and AA40, attacking (and defending) subs may avoid fighting by submerging at the beginning of the first round if there are no opposing destroyers.