If they are on visa once they leave Qatar the visa is void (single entry). I dont think Pakistanis can get visa on arrival in either Qatar or the U.A.E.

Also, for crossing the Saudi border all people in the car should be close relatives (woman accompanied by a muharram). I am not sure how it would go if you had a cousin or siblings wife in the car with you and the ladies must be covered. Check that as well, if you dont ask in the embassy you may be denied entry.