I'd imagine that their behavior goes back much further than that before the MC showed up in town. But between Mika, Catherine, Chloe and Vicky I think Mika was the worst by far.
Only Vicky has apologized to Lucy so far. If Chloe wants to get anywhere near the harem she would need to do at least that. I don't think she will ever be more than background character tho, but her peeling away from Brian would be sweet for sure... We already saw less and less of her with Brian and Mika before she showed up at the goth competition. Maybe you're on to something here?
I mean, it's not like we have seen much of Chloe, period
We have one scene where she speaks and it's mean girl bs, mostly to Victoria (and, by the way, I wonder what those rumors about her a few months ago were? It's never explored upon). After that is her mostly looking surprised/shocked - not a lot to go on. But Cosy has been pretty pedantic of setting up facial expressions and body language, I think he meant to convey she is thinking about stuff.
That said, I'm pretty sure she ain't joining the harem. There is a list floating around with all the Main LIs (those who will get collars), semi-main LIs (major role, but no collar) and side chicks and I think Chloe is in the third category. Granted, I'm pretty sure Annabelle wasn't in any of them or was in the last group initially, so, Cosy is not above promoting a fan favorite
