Last F16 MLU were done TAI , so any future modifications or even upgrades if we able get hand on used one will via path of TAI
Turkish getting block 70 mean they will also get hand on latest avionics and tech of f16 with them
Pakistan's foreign relations with US are not the same any more, as they used to be during Musharraf era.
In present times, without GCC support and sponsorship, it's impossible to break any defense deal with US. This includes MLU kits, MLU work may still be done in Turkey as you pointed, which was a business for them, as well negotiated by Musharraf.
In order to visualize present day situation, you can take example of Jordanian F-16 deal, which materialized due to strong diplomacy by GCC friends.
Similarly, if any time in future Pakistan managed to break Egypt F-16 deal, it would again require convincing US, whereof Pakistan's foreign office holds ZERO value, so once more PAF will go running to GCC for their diplomatic support, to win favorable US decision.
Turkey getting blk-17 means nothing for Pakistan. In fact it's UAE who holds a parallel position as US in case of blk70 sales. I trust UAE approval is part and parcel of Turkish F-16 deal and in similar manner for the new Pakistani F-16 deal, which bro. Khafee broke to the audience.