Congrats on your purchase, details please
Im sure there is a legal way around your hitch. You may go and ask the local motor vehicle reg dept in Lahore and find out the procedures.
I guess the owner's current ID card's copy (be it from Canada/NADRA overseas ID card etc), a copy of his last Pakistani ID card and a letter from him saying that he is selling the car should be sufficient. You may send him a scanned copy of a transfer letter/sale deed for him to sign and post back by snail mail/courier.
Best wishes and regards to all.