Doesn't matter what will the size of IAC-2, what matters is that no other fighter than Mig-29K, N-LCA and one out of N-MRCA contender will equip IAC-2. And with this no, F-35 is surely ruled out.
As far as N-FGFA is concerned then yes its true that Navy aspires to equip IAC-3 and onwards with FGFA. For that they have already started preparations way back in 2003 and that was done with the decision to support N-LCA program. It is widely assumed that with this program navy is trying to hit two targets in one shoot, first is getting small agile fighter in number and second is to develop expertize in developing carrier born fighter planes. And navy will not allow second to go waste easily, they are sure to use this know-how acquired in the development of N-AMCA and in all likelihood development of both AF-AMCA and N-AMCA will be done in parallel.
There was always a plan to develop naval PAK-FA and first interest for it comes from Russian Navy, which is looking to equip its new carriers with FGFA........ Looking at the size of upcoming Russian carriers i can claim that they will fall in same class with IAC-3 and with that IN will get another option, which i think they will definitely exercise for flexibility.
I expect N-PAK-FA come by 2020, N-AMCA by 2022 and IAC-3 by 2022-23. With this i can conclude that when need for putting FGFAs abroad carriers will arise then IN will surely have two non american FGFA in sight to choose from or choose together.