I didn't said they were meant to replace F-16s. Yes these were to counter Rafales and restore the balance that was disturbed by Meteors+Rafales.
If we have all the money of the world, We all can deduce easily that let's replace Mirages with J-10Cs and F-16s with J-35s but that's not the case. PAF is still flying 60 year old Mirages for a reason that is lack of funds. Even to produce JF-17 there's a lot of cost that is attached. So financials are always to be understood. Your procurement plans evolve based on the economic output. So, if the economy do not allow all F-16s to be replaced by J-35s then you will have to replace those with the mix of J-10Cs & J-35s.
BTW, who has made a hard & fast rule that only mirage is replaceable by J-10C and F-16 by J-35 ??, There's nothing such thing. It all depends upon circumstances + economy. In the 90's, PAF was desperately looking to buy aircraft, sometimes there used to news in newspapaer for mirage 2000, sometimes for Saab, sometimes even SU-27 before JF-17 was materialized. So at times, you have to be driven by the conditions & circumstances and not by the ideal fit that you have had envisioned. Even 2 squadrons of J-35 and 4 to 5 squadrons of J-10Cs in the entire 2030s will make PAF a very impressive and powerful fleet. We don't have to crave for unrealistic goals. The 90 figure thing for J-35 is achieveable by 2050 not anytime sooner.