Who is the ghoul you have to talk to at Necropolis to get to the water chip? I may have killed him and doomed my save. A while back went to necropolis and killed a bunch of ghouls without realizing that they may not have been hostile.

There's no one you have to talk to.
Though you can talk to the guys in the sewers, and Set. Set is in the "Hall" onhttp://planetfallout.gamespy.com/wiki/(6)_Necropolis map.

Ok so now I have been captured by The Unity, I am in a cell do I just wait or do I do somthing, I can't pick the lock.

If you've been captured in Necropolis, unless you're of a particularly high level, I'd suggest reloading. You get taken to the military base, and thats really end level content there.

Really? I am just trying to get the water chip still. good thing I saved it on a different save just incase.

Yeah, its full of supermutants with Plasma rifles, Gattling lasters, and other fun stuff... But you'll get there.

Best advice I can give with the muties in Nec is to pop down some mentants and convince harry you're a ghoul (its not that difficult). If he's convinced, the others will just leave you alone.

I would recommend saving each new save in a different slot, working down and then starting again from the tops. This helps safeguard against losing masses of progress due to a corrupted save, big mistakes, and situations like this.

Harry and his kindred arent that hard to kill, get into a room and kill them as they try to make it into the door. Or you can try sneaking past him, or just use the combat bug, basically open up combat move x steps right before you use your final AP spam the combat hotkey puts you back into it before he can ask you anything. Rinse and repeat.