I have added some Bandits and Necromancers to fight in my dungeon. But for some reason, they do not appear in-game. I did use the ping-pong tactic on some of them, does that have to do something with it?
It does sound like you need a http://www.creationkit.com/Bethesda_Tutorial_Navmesh. Whenever Actors don't appear or don't move, that's usually the problem. Usually.