Responses

Unless she does something which she hasn't there's no reason to assume what they are. So far she seems like an outside observer commenting on the central relationship in a way that couldn’t happen with one of the other girls without changing the core group dynamic. Since you know they still don't know that they are dating. Like even in the latest chapter you see the Kouhai try to help Chidori in a way the others can't. Its like you guys just want to hate her for that one comment even though nothing has happen.
Awww, the kouhai is just a gay bean