That doesn't really equate imo. Obviously this discussion is lighthearted as we're just debating made up characters, so I'm not taking this seriously as it all just boils down to Selebus. However, I think the issue is not that girls wouldn't do this, but that she goes from 0 to 100 out of nowhere. This makes sense inside the resets, but not really in real life. While certainly possible to hit on a teacher for personal gain, to straight up flash him while having no experience whatsoever in sexual matters is uncanny. To go from that to sexual assault and blackmail is even more so.
Aside from that, and giving my two cents: I agree that Futaba is one of the most realistic ones, but rather than Kirin, I'd add Otoha to the mix.
In fact, for all my distaste of her, she behaves exactly like a common teenager. In what world wouldn't she develop a crush on Niki and "shoot her shot", as the youngsters say, given the chance? Rin, for all I love her, puts herself time and time again in a position to be taken advantage of, and that's what Otoha does. As, sadly, a lot would in her situation. "A girl is throwing herself at me, while the one I want doesn't even see me, and I can use this person to get some experience to maybe have a better shot at Niki? Count me in". I wasn't always a mature old goth chick, and I don't know if in Otoha's position (and mainly age) I'd have acted differently. Well, I never cheated on a partner, so probably not that, but for all the rest, I don't know. So yeah, I think she's very realistic.