No, quite the opposite. Kas fled Mareth concurrently with the Champion of Ingnam assaulting Lethice's palace. How that assault ended is left ambiguous in CoC2, since CoC1's endings are so incredibly varied.
We'll be doing a sweeping set of updated talks for things like this near the game's final build(s). Not much sense maintaining it constantly over time.
Not much different. There's really nothing major I would want to write for her that I didn't. It just would have made other people adding content with her a lot easier haha.