The clothes thing. A loose though.
In all her interactions with Yukako post-reunion, she seems to be wearing more masculine clothes (suits, shirts, pants). She rejected the skirt Yukako picked for her and now, after looking at her body in the mirror she is tossing all her feminine clothes. What Yukako said when they broke up seems to have left more long-lasting damage than was shown until now. It might be that she is rejecting her femininity to try to get her back - she wants to become her "man" because otherwise, they have no future. Or something along those lines.
It's too early to analyze Chinami like this but it's not a bad reading of the character's intentions.
I'm curious though if Chinami's genuinely in love with Yukako (the way Yukako is undoubtedly in love with Chinami after all these years) OR she's just in for the satisfaction of an illicit lesbian affair just to hurt Yukako later on.
Cuz I feel like every time Chinami reminisces the past with Yukako in it, it's just bitterness and she seems on the edge/verge of something like a time bomb.
I can't wait for the next chapters.