So where are the people (ghouls?) after you transfer control to them? Or can you find them? Also is the overseer an NPC you can talk to or just a ferral ghoul?

They sometimes go to the Aerotech offices a while after you free them. And move this to the spoilers section, of the New Vegas game section.

This should be moved, its got nothing to do with DLC.

Agreed.

Ack oops that's what I get for posting speedily from my phone

They move to the Areotech officers and reward you with xp. If you don't rescue them you get less xp but NCR fame.