From what I can tell, I charged the witch too soon, and Lord Barrowgrim never left, the witch dies, barrowgrim is still there, and Ellowyn is still trapped. I didn't think to save before the battle; my latest save on it is only after it glitches - help!
There were four blue orbs in the cubby holes. Dumping these in the fire pit on the main platform weakens the witch. Once you kill her, get her life orb and dump it in the fire pit. Now the young lady is free.