There's no advantage to replacing the water pump during this operation. Almost nothing of what needs to come out of the way to get at the pump, gets taken off to remove the head.

If you are one to remove the manifold WITH the head, which is not my preference, then I expect that it would help some, but I think the P/S pump would still have to come out. I might be wrong because I've never pulled the manifold with the head.

Good luck,