He isn't in befallen. Waited through several spawns there between the stairs and he never showed. This is a good reason why it shouldn't be delayed and cut short.
Having read that he spawned on the bottom floor, I dropped down through the traps in the floors to get to the lowest level, then discovered I couldn't open the door to get to where he actually was. As an enchanter, I used gnome illusion to see through the locked door, then used the "cycle through nearest npcs" key to target him (/tar Wraps didn't work from that distance). I said "trick or treat" and got the candy, then gated out. Hope this helps anyone else trying to get to him.