This is my first time posting on these type of forums for a while, but the topic peaked my interest enough to listen to a bunch of Chinese podcast. So I will say the following.
As much as J-10 export have been discussed for a long time (starting with J-10A long long ago), it really was not very simple to do it until now. And the reason is J-10 have been equipped with AL-31 until the last couple of years. It's one thing to get Russians on board with exporting RD-93s for 150 JF-17s. It's quite another thing to get Russians on board for 25 to 40 J-10s. Now that they have a reliable domestic engine that can be produced in large numbers, they have the ability to both supply domestically and export. China and Russia have very tight relationships. You are not going to see J-11B or J-16 ever get exported to Pakistan. Even though it's of my opinion that J-16/J-16D are more powerful than J-10Cs, China will not piss off the Russians. The next aircraft China will like to export to PAF after this would be whatever comes of FC-31. But who knows how long that will take to get fully developed and mature.
Internet warriors make a common mistake of getting overly excited about possible future capabilities and not about what makes sense from delivery and price and training point of view. It's more important to get aircraft into your service quickly that can immediately improve your training and capabilities rather than continually waiting for an exporter to develop new technology that may take years to be completely certified and reliable. That's the difference between China and India. That's why China got the MKK quickly into its service while the Indians spent days glamorizing MKIs mythical capabilities that took years to get there. Keep in mind, even a "mature"/conservative design like MKK still took years to get certain capabilities that Russians had promised.
J-10C is a no brainer for PAF right now for some very obvious reasons. It has been in service with PLAAF for 6 years and should be mature/reliable by this point. It's been flying with WS-10B for a couple of years. They should've fixed most of the issues by this point. PLAAF has trained with it for that many years and have a good idea how to use it and can pass along that knowledge to PAF. PAF has also trained against it several times with all the joint exercises. In the event of a war, China can send J-10C replacement to PAF at a very short notice. There is a mature production line in CAC, which means cost of production will not be high. I'm sure J-10C will be more expensive than JF-17 Block 3, but not that much more. I don't expect PAF's J-10C to look exactly like the PLAAF ones. From what I heard, PAF's version may turn out slightly limited due to budgetary issues (not because PLAAF is limiting export of any technology on there). PAF is getting J-10C for very good price. Aside from that, PLAAF will likely help PAF with maintenance. PAF will have no problem getting spares from China, since PLAAF is going to have a large J-10 fleet for a long time.
And finally, China is able to deliver J-10C to Pakistan at a short notice. I'm sure the PAF J-10C have been in production for most of past year, but getting 25 of them by March is rather impressive. How long did it take IAF to get the 36 Rafale from the time MRCA was announced (20 years)? It's been 10 years since IAF had announced Rafale won the competition. I'm sure China and Pakistan have been negotiating this secretively for years, but they probably only made the decision only in the past couple of years when Rafale started to operate with IAF. Make no mistake, Rafale is a great aircraft. A lot more capable than Su-30MKI. Anyone in China will tell you that JF-17s with AEW support can handle MKI pressure. J-10C may or may not be a better aircraft than Rafale. But in the context of operating in an environment with other aircraft, AEWs and ground radar support, it should be.sufficient in matching that thread for PAF. The sooner that PAF can get J-10Cs and train with it, the more capable J-10Cs will be. Also, keep in mind that in the future, you maybe able to upgrade your aircraft significantly through software upgrades and small hardware upgrades that would be hard to notice from pictures. With the amount of resources China has dedicated to this area, I'm willing to bet J-10C will see significant performance improvements in that way. The investment that China and PLAAF has put into J-20 development will also show up on its other aircraft in different ways.