There is / are F-22 based out of Afghanistan, USAF likely knows what it needs to know about the KE-3s, JF-17s. I wouldn't be surprised if there was an F-22 present in Pak airspace during the Shaheen-VII exercise. I am not trying to make USAF sound like something that is invincible but they are real good and have some kick A## equipment.
Let JF-17 go against the F-18, let them do a real "What you can do, i can do better."
PS: I don't think PAF is going to buy any new F-16s ( Block 70 or 80 or 90 ). If PAF was interested in paying 100% out of its pockets, they would have signed for the 8 that they passed on. Now that being said, PAF is very likely to pick up used if they can get OK from US Gov't. Biggest hurdle would be getting OK for the best MLU to what these jets can get. PAF is getting AESA, its a mute point for US to hold that upgrade, only issue would be the Indian Sponsored lobby jacked up on Indian Business Communities funding.