If they were to make a 2nd gen 86 it would probably just be a very heavy updated and reskin version of the current car. I recall reading something awhile back that said most "next gen cars" usually retain around 30% to 40% or so of components from their predecessor.
The differences between the LC and this car is that Toyota had already filed trademark for the LC500 and LC500h back in November of 2014. So far to date, the only two names Toyota has on hand is Supra and Celica.
If its going to smaller than why did the press release say it will be a midsize sports car? :what:
https://www.press.bmwgroup.com/global/article/detail/T0136503EN/bmw-group-and-toyota-motor-corporation-deepen-collaboration-by-signing-binding-agreements?language=en
Just from a marketing position, I think it would be smarter to just call it "Toyota Supra". When polled, a majority of people did vote for the Supra nameplate.
http://www.ft86club.com/forums/showthread.php?t=53322
http://www.supraforums.com/forum/showthread.php?746321-Toyota-debuts-FT1-sports-car.
Wasn't it Jack Hollis that made the decision for the 86 to be sold as a Scion in the US? That was probably one of the dumbest decisions Toyota made marketing wise.