Oil pump priming. Vaseline needed?

Air in the system? These are positive displacement pumps and will pump air. You dont need to bleed the air out of the system to get it to pump like you would with a centrifugal pump.
No need to do anything to the pump. If its a new engine or been sitting a long time you should prime with a priming shaft / drill. The filter does not have to be completely full when you put it on. Fill it enough to soak the element and thats good enough.
Bottom line is the pump should be able to pick up suction even when dry. If it wont then the pump or pickup has issues.