Based on some of her dialogue was she intended to be an ally? Is she meant to die by the other vamps? Can she make it back to morthal

She stays there if she survives. At least from what I've seen.

She stays there during the day but goes to the Morthal inn for dinner at night, returning to the Lair during the day. I find that a really cool routine and so I try to keep her alive during the quest.