Can Pakistan afford FC31s? even one unit would cost almost 70Million and you would need two dozen to make it worthwhile not to mention upkeep cost
They can always sell assets.
70 million might be the PLA's own internal cost, since even export J10Cs sell for almost that much, an export J-35 is likely to be no less expensive than a non marked up F-35. But if Pakistan wants to offer something for it, there is defintely a capability to do so.
If Pakistan can fix its civilian economy (and it has been doing better recently), having the 1st 5th gens in the subcontinent could benefit them greatly, in terms of prestige, especially now that things are heating up in the Arab world.
But can China sell them without fears of sensitive technology leaking to enemies? Then again maybe it is OK, as long as the export 5th gen is made sure not to be revolutionary compared to the F-35, since those have already been cabbagized due to exports.