if EMALS package goes through with IAC2 then options for IN as part of packaged deal would be either of US Super Hornets F18 NG or carrier version of F35 - F35C. Since the hornet program and its line is coming to close in 2017, the chances of it being offered and rejected as was in MMRCA too is very very high. This leaves only F35C as potential packaged product with EMALS. Certainly you can see close to 60-80 F35C or may be max 100 (including shore based or for IAC3 too) as part of the EMALS package . These would be off the shelf and at best if US and the F35C program members really agrees we may get Kit assembly but i believe it would be off the shelf only.
The numbers can be guessed only but if IAC2 is 65k tonnes then about 3 squadrons or 45-60 bird a surety. In case its bigger then may be 80-100.. (super carrier nuke powered)
Again, what US may find very challenging is if IN also prefers Rafale M as part of commonality program if MMRCA winner Dassault rafale signs the contract of 126 birds. such a case the whole rafale deal may get to a massive 200-250 birds size as 126+63+45~60 ===234-249 ~250 birds. This may tilt IN to look at rafale M to ease its operational cost and training needs....