Intresting strategic situation!
What state is Mongolia in is my first question. You mentioned some of the true neutrals being under axis control so Im wondering if this has impacted the Soviet-Japanese front. I am glad to hear that Japan is able to maintain is supremecy on the Asian mainland after Russia starts helping China. I assumed that once the US got into the fight, and could focus all its 80IPC strait at the euro-axis it would be very damaging, even more so in your game after what sounds like a pretty nasty brawl over there in London!
Now seeing as how you have reached the end of turn 5, there are 2 way I could see you advance.
1 would be to keep playing the game out and see how much longer the Euro-axis can hold out and try to break the dead lock Japan and the Sino-Soviets forces are in.
2 you could bring the Soviets and Japanese in to their new alliances as full members, not just defacto. It would be intresting to see how a full Axis Soviet Union would effect the game, and the same is true of allied Japan.
Would this be the tipping point? Would this give the Euro-axis the shot in the arm it needs to stand up against the allies, and will this give Japan the edge they need to break deadlock in Siberia?
Also, how dose this effect China? since the Soviets and allied with them, dose this make them axis? Should this take away the Chinese Burma road NO, seeing as how they are at war with a British Ally? What status dose China hold? Are they defacto axis? If fighting breaks out between the Soviets and the allies, dose it make China a full axis member? Or dose China have the unique status of being an unaffiliated beligrent, a Playable Neutural power, if you will
I excitedly wait to hear what you do, and thank you again for testing this out! :-D