Some good advice here – I like the idea of Japan coming for Russian’s far eastern territories, and I agree that Leningrad is a ‘must have’ not a ‘nice to have’ for this strategy to go well for Germany.
I’m not sure I understand the part about waiting for J2 to declare war so that the US doesn’t reinforce Gibraltar – US Atlantic fleet at start of game is only one transport, one cruiser, one fighter, and one strat bomber – there’s no Allied carrier in the Atlantic, so the planes would have to land on Gibraltar itself. Britain doesn’t have enough ships to protect SZ 91 against both German subs and German planes, even if you add that one American cruiser. Italy should be able to take either Morocco or Gibraltar on I1, depending on situation, so German planes can land. So anything the Allies send to SZ 91 on turn 1 will die on G2, I think. If America wants to head over a turn early and get itself killed, great!
With the forces there, italy will have 1 transport available so 1 inf 1 tank and a bomber
Against 2 inf and a tank or 1 inf 1 tank and a fighter, those are pretty shaky odds at best.
UK can land in Moroco with the forces from canada or UK proper, US can land 1 transport and plane in gibraltar.