This makes a lot of sense. Just my thoughts here are that China actually thinks about India much less then people imagine. They no longer see it as a threat, the main vision they see India through is as a market of 1.4 Billion people, China wants this market on it's own terms.
Pakistan is no longer seen as just a balance to India anymore, we are a physical, diplomatic and military way for China to expand it;'s influence westward. Pakistan itself is cocking that up a lot on the economic front with delays on CPEC projects, mismanagement and bad Balouch security situation. On the military and diplomatic front we have played a blinder and China is involved.
Chinese backing for Pak mediation efforts and Pak introduction of advanced Chinese systems in GCC for the first time (yes, I know GCC has some Chinese stuff already but am talking Fighter jets and SAMs).
In this light, J-35 in PAF service helps China is several ways
1) Balances India, or even to an extent makes IAF lagging behind PAF for first time ever
2) Shows world a first class air force has inducted Chinese 5th gen, and possibly provides another testing area if we go to war again
3) Opens up Mid East to Chinese kit. Like we did with J-10 expect to see J-35 exercise with close Pak allies like Qatar and Saudi who will see J-35 close up, now also remember we train A LOT of Qatari and Saudi cadets at Risalpur and we have quite a few people on deputation or as contractors in both