Mutual gain with feeders is coming relatively soon, as the smaller update I'm currently working on will let you fatten feeders.
Personality-specific stories are absolutely something I want to do. They will be in a future update, but not the next big one (they would have been part of the 'More Personalities' option, which is currently in third place in my poll).
I definitely plan to add more customisation options & more personalities in the future too. Please feel free to suggest anything you'd particularly like included!