Can you please tell us more about payment plans that Pakistan typically gets from China for gov't to gov't defense deals, and/or how the PAF's J-10C fleet was financed?
If you have any articles or papers on this topic in Urdu (or English), please don't hesitate to share!
Not trying to impose, but a better understanding of how Pakistan finances and pays for its defense imports may shed some light on just when and/or under what conditions the PAF will officially induct the J-35 into service.
Chinese sources have compared the HQ-19 to the THAAD and the proposed THAAD-ER; and IIRC, it was in fact designed and engineered with defeating Indian IRBMs like the Agni III and IV as a baseline requirement.
So the HQ-19 can definitely add to Pakistani AD capabilities in a meaningful way.
The problem is that it's an expensive system, so it's going to be tough to acquire enough batteries — even if localized production is made possible down the road — to safeguard Pakistan's many strategic C2 nodes, special munitions depots, major airbases, etc.
I'm sure that maybe this is mentioned in articles and such but from what I've been able to gather, the payment plan is more or less "pay us when you can". Often times part of that payment too is either deferred or waived and that is on top of the price that we get on the stuff which I've heard is usually discounted. Or it may be that the Chinese are given concessions and preferential treatment elsewhere in other deals. The gist of it is that we're not under any significant pressure to pay for this stuff.
I have no reason to disbelieve that an arrangement such as this exists bearing in mind what I've heard and seen but most of this stuff is not reported upon and considered to be an open secret.