An idea I had. Next gen carrier fighter is obviously not going to be ready in numbers for 003 carrier, possibly even the carrier after that one.
We've seen catapult J-15s also being readied.
In USN, we've seen a size creep over the decades. Basically, a bigger plane is always going to be more cost effective than a smaller one.
Since 003 (and later carrier) will have to be sized to operate J-15, and since it may very well be prudent to use a fairly large plane to perform all the future missions, especially given that the carriers will already be sized for an even bigger J-15,
I have a tingling feeling that the carrier borne J-XY, the FC-31 derived plane - is NOT going to be completely the same dimensions wise. I expect a fatter, possibly slightly longer plane, and definitely one with larger wings and other control surfaces.
So, while it will likely very much resemble the FC-31 demonstrators, i wouldn't be surprised if the final differences will be closer to what SuperHornet featured compared to the regular Hornet.