Ok, here I am.
First of all, like kingmaster1 wrote, I don't think that the "sexual slavery" of the teacher (or teachers, given the Haibane-colleague idea) involves food & water deprivation, lack of hygiene, actual torture or acts of random cruelty. What we're talking about - and please correct me if I'm wrong - is [quoting!] pleasurable bliss, turning her (them) into their slut(s), and she's (they're) supposed to like it, even if not admitting it.
Marie: I don't mind at all another girl in the team, a submissive-oriented friend of my brilliant Tammy. Your idea sounds interesting and funny to me.
Haibane: another teacher to "enslave" sounds like lots of fun! I like it! But if Haibane prefers, she can play the role of many minor characters, I don't mind this idea either, even if I vote for the colleague.
But please, let's not involve too many players, or the game is going to get too confusing. In my modest opinion, a team of five is perfect.
Let's hear a word from Kythia and then we can start, can't we?