depends if your blitz has optical joysticks. or regular 8 ways. If its optical, you need to replace them first. the only game that uses those optical sticks is gauntlet.
The cabinet is jamma. So it should play nba jam or extreme. adding player 3 or 4 might be a bit of work as the connections might be different (I have both boardsets, but I have never hooked up player 3 or 4).
But if you were asking if you can convert a seattle blitz pcb to play nba jam or extreme, the answer is no.
also if your blitz has a medium rez monitor in it (dedicated is usually medium rez, kits are usually standard), then no as nba jam and extreme is standard rez only.