A stealth 5th gen single engine mid weight fighter? Why would that be necessary for China? I doubt Russia will be the main customer with this fighter and would be willing to bet Russia will stick with heavy weight fighters unless this aircraft actually offers more range and payload than something of its size e.g. F-35.
China prefers heavy weights as well with J-10s only filling the numbers role and having much more restricted and dedicated positions due to range and payload limits.
Something like this would be rather useless for China especially if it has to go to the trouble of developing one. If there was a need to replace J-10 with a 5th gen mid weight but single engined like Checkmate, PLAAF can buy it off the shelf. Except I very, very much doubt China would unless India places a large order. Gotta owe it to yourself to fly what your potential adversaries will fly if the opportunity arises. Remember the US has stolen or purchase and "acquired" many Soviet and Russian missiles and aircraft in the past. Not only to learn and study from for weaknesses and strengths but also to actually test and verify their counters to them.
Indeed funding and time shouldn't be wasted on yet another 5th gen program, especially a J-10 replacement class aircraft. There is no more advantage having a stealth midweight single engine since at that point of a conflict, the advantages of stealth are worn out. J-10s class is there not to engage 5th gen platforms. Making them stealth must return less than investing that into fighters with more... everything. The handle of a spear doesn't need to be as strong as the tip. It needs to be more numerous and I can't imagine a single engine stealth fighter to be cheaper than a J-10C to buy and run. The only advantage it would have is VLO but could have even less payload if VLO is preserved. Where you use the filler is not where VLO is quite as necessary or desirable (payload). Therefore effort and resources towards the sharp end of the spear rather than pointlessly filling up the handle.
If there wasn't this optimisation or point of diminishing returns, the USAF would never have continued developing upgrade for and buying 4th gen platforms. There is a point at which more 5th gen fighters is not as effective as simply upgrading non 5th gens and spending the balance on the next projects.
