There is a couple of things I want to address here. First of all, I would consider WS-10 to be quite mature by this point. It's true that back in 2015, AL-31F probably did have long service life and reliability than WS-10. But we've gone through several years of flying now and PLAAF have been using its on J-10C for a couple of years without any major incidents. The original design spec for WS-10 had higher MTBO requirements than AL-31. Now that both engines are mature, I would imagine WS-10B currently would have better in service MTBO period than AL-31FN. More importantly, China is now producing massive quantities of WS-10 every year. You are probably going to have better after service care from China on WS-10B than you would from Russians on AL-31FN. IAF's AL-31FP issues with Russians is pretty well known. I'm not sure why people are acting like Russia is the hallmark of reliability. It's pretty bad.
Secondly, we've only had the one known J-10C prototype with TVC. It would be quite crazy for PAF to opt for that.
Thirdly, I actually don't think F-16V is a good choice for PAF at this point. It probably is an adequate option against Rafale, but there is not much growth left in the F-16 platform. F-16 at this point is maxed out in terms of what you can fit in there. It's already lost agility in order to fit AESA radar in there. In comparison, I think J-10C at this point can fit more larger/more powerful radar and electronics in there and will probably have more powerful engine to support that. There should be some growth left in J-10 program still.
Fourth, I don't get this fascination with saying that PAF never compromises on quality and always needs the best. That's simply not true for any Air Force, let alone when that faces a massive resource disadvantage again its biggest rival. The only Air Force who can always get the best is USAF. Everyone else, including China, needs to be realistic about their options based on who they can acquire from and what their budgets are. If you want to use IAF's strategy of shooting for the moon and fantasizing about exporter's marketing brochures, then you are going to end up as a smaller and weaker version of IAF. That would be a terrible strategy for PAF. PAF needs to make cost conscience decisions on what's most available that can immediately improve its capability and allow it continue to be a strong deterrence to an opponent with massive resource advantage. Getting J-10C now is about getting a strong deterrence against an obvious threat to balance of power in the form of Rafale. PAF cannot wait 5 years and sink a bunch of money into getting something else that looks good on paper. It wants IAF to continue to keep doing that.
I agree 100%