I think they're supposed to continue the theme about what makes for a healthy bdsm relationship by demonstrating more ways that things can go wrong. Each of the members has a selfish and unilateral perspective on things that doesn't involve communication with or enthusiasm from their targets. We've got a voyeur/IRL shipper who doesn't seem to care at all about the girls she's observing and only about titillating for herself. We've got a girl with an unhealthy amount of obsession and devotion that seems to be one-sided. And I think Imitatio, who we can see can dish it out but can't take it, is someone who refuses to go along with her partner in a scene and instead is just imposing what she wants out on them. Compare her to Utena, who tries to "see" the person she's tormenting, who has a strict code of honor and cares a lot about making sure her play doesn't cause permanent harm, and is prepared to put her body on the line when domming.
It's not fully clear yet, but I think I'm starting to see the themes.