For Pakistan, J-35A acquisition will present several challenges.
Even if China provide at reduced costs, lifetime support, maintenance, spares, costs will be more than the planes itself.
Repair, and maintenance for stealth will be additionally difficult.
Fixing Composites, Airframe skin, RAM, will be costly unless Pak builds a separate infrastructure for repair and maintenance, which will be challenging in the absence of domestic mature know how.
This is while China has not finalized the engines, and still developing WS19 or any Western comparable engine.
May be just replace engine every 3000-4000 hrs!
How can an unproven, unmature turbojet can be installed in a 5th Gen Fighter?