Ok, put it into the calculator. If:
- no hits are taken by the Japanese fleet in any attacks
- all the ships which can reach Caroline Islands go there J1
- no assistance in J2 from new units or units starting in SZ19 or SZ20.
- US Hawaii and Philippines fleets move to Western US or Queensland respectively
- no IJN blockers (not much point if they’re only blocking the US DD and Sub from Philippines anyway)
- US Carrier moves to the square adjacent to Hawaii (SZ12) allowing two more land based fighters to enter the combat
- All US ships in the Pac join in
- US loses Hawaii on J2 after evacuating its ships, troops and planes
The odds equalise roughly if the US buys 3 subs in the Western US. Of course, they can only buy 3 units there if not at war US1. But throw in another Strategic Bomber at the Defender drops to 25%. Buy 3 Strat Bombers and only 2 subs and the defender drops to 8%. Of course, that does mean you can’t buy a destroyer for the atlantic on turn one.
Let’s say that maybe they feel like making a stand at Hawaii on the land battle:
They can fly in 2ftr + 1 tac + 1 stratB, in addition to the 2ftr already there. Let’s assume they play it safe and leave the stratB at home. The Hawaiian defenders survive this 88.9%, even without reinforcements from the mainland or with the reinforcements but sending on the Hawaiian troops to Qld - SZ54.
I’m going to take some convincing this strategy of yours is impregnable.