Taking Calcutta or Burma is the equivalent of taking Yunnan or Szechwan: No NO for China.
Unfortunately for the Chinese, if Calcutta or Burma is lost you will require Allied intervention to ever get that NO back.
AFAIK China can never leave its borders.
China can attack Burma, but not Calcutta. If Calcutta is taken by an axis power China has no chance getting NO by itself. It needs the help from another ally.
It depends on the japanese moves.
If Japan is going for China or otherwise out of position you can get some extra money from the NOs for UK pac and ANZAC.
In one of my last games japan was too deep into china and out of position to be a real threat for UK pac. Japan had to move into position, UK and ANZAC got the money for their NOs for two rounds.
There has been another update yesterday:
11/17/11 US NO change: 5 IPCs for each turn that the US has at least one land unit in the territory “France”. Theme: Great Alliance collaboration