How many transports is Japan buying on J2? in your counter
Either way on UK2 and UK3, one turn could be used to buy 2 fodder ships for the aus fleet if they are not destroyed on j1, additionally 2 more inf could be loaded up in aus, plus the help of an american fighter. japan may not even be able to take it back. also, if they do, pulling those transports out of the asian dumping requirements kills germany. this becomes a huge distraction. and if you slowly add to the us navy in the pacific, which you should base in alaska, you force japan to invest in ships.
As for the losses in africa, the US can start dumping a few in there.