What confuses me more than anything is what's inside the tower at the end. Are you supposed to be able to interact with those undead at all? No matter what dialogue path I took nothing came of it, and the only way through the large door was to teleport someone through the hole in the wall and open it from inside.
I found the key for the door!
I buffed myself with Clear Minded and Rested and then was able to see the key on the corpse of Necromancer Tasmyn (may have had a stat check to find it).
For some reason, all of the skeletons were dead for me when I got there. Was this because of smashing soul jars?
I wasn't able to teleport anything through, so I had to find the key.