It’s called the J-31, among other designations.

This one is much more similar to the F-35 and the F-22, so my guess is that this one is later to the game, and it’s probably intended more for the air-to-air role.

It’s appears to be about the size of the F/A-18.

I can’t speak to its level of stealth, but considering the fact that it won’t carry the overhead that the F-35 caries by having an STOVL variant my guess is that the performance would be roughly equal.