The J-31 looks to be a MiG-29 sized YF-22 (not F-22) knockoff with the somewhat more stealthy F-35 inlets and smaller nose. It uses MiG-29 engines (either ones obtained from Russia or knockoffs)
It is rumored that ChiComs has almost talked Russian export control into allowing them to get a newer ‘item 117’ type engine designed for Sukhoi version of Raptor from Saturn Co.
It would make ChiCom fighter much more appealing.