Isn't it weird that NOT talking with Isobel is a better choice all around?
I know some people just love to fight any battle, but story-wise we avoid:
1. The battle which even if successful (Isobel is not kidnapped) can result to the death of some characters around the Inn.
2. Mol being kidnapped.

Do not talk to her and you are good, the end result is the same if you choose to free aasimar (maybe it's even the same if you kill her, I haven't tried), so why bother?