1. Yes, but in the next update the carp monster will be recruitable.
2. Possibly, not sure how I would go about that yet. (Possible idea that just came to mind is maybe bringing back Asher's basement expansion concept from the original game, just maybe not made by Asher if you get what I mean)
3. Not yet, that is a whole quest (that is sort of like the rebuilding of the snake den, but with different requirements and stuff).