Yes it seems that SAC and XAC will collaborate to develop the multirole stealth fighter. This aircraft would also suit perfectly PLAN future needs.
Personally I preferred the theory that J-19 was a heavy twin engined aircraft dedicated for strike, with possibility for future carrier modification. We'll see.
may be they have already flown a small scale demonstrator months ago. Do you remember?
I was thinking something more along the lines of X-45A to X-45C or phantom ray -- small scaled proof of concept aircraft developed into full size combat capable planes. What you're talking about were less demonstrators than model planes, too small to demonstrate much apart from that flying wings can fly. the fact that those toy like models resembled flying wing ucavs is more likely to be from benefiting of research for said UCAV than actually being a miniature scale demonstrator.