There wont be anything coming forth from MiG, that could credibly called a separate concept, in my opinion. They barely avoid being absorped into the Sukhoi-complex by means of the UAC these days. As long as they cannot find more cash from credible exports, MiG is not going anywhere.
The very initial concept of PAKFA included two aircraft, one single-engined, one with two engines. Basically a F-22/F-35 idea in one family package. However these ideas were shelved years ago due to cost. It will be interesting to see how exactly the workshare will be arranged for PAKFA, as far as Sukhoi and MiG are concerned. I havent read much about that yet.
As far as the Indians are concerned, there seems to be nil credible information beyond the fact that they, in one way or another, contribute financially to this effort. There is a lot of politically motivated lip-service to a cooperative effort, but as far as the Russians are concerned, they really just try to dig up more cash to pour into PAKFA-development. What exactly they are getting out of it remains to be seen really.