3somes are an interesting proposition.
Both of the twins seem to have a sort of sub-streak, whether openly or in some fantasy; I think they'd actually get along well with f.Ex. Lin in the future. Then again, the fascination of a threesome doesn't match very well with multiple subs, unless you just want to deny one of them.
Maria could work, but I guess Android is also a possibility, given that she has a Dom Mode and could probably be reconfigured anyways.
Besides that, I'd like to voice my approval on that Ashley Date(I think I never wrote that); It's nice to see the character has some actual character.