A Chisato x Kanon doujin by Mezashi??? My life is now completed, I can die peacefully now.
Anw, personally I really like Chisato story. It made sense to me and I can kinda relate to it. For Chisato, dancing is just a mean to an end. She just needed it to prove that she can be good at something even without Kanon's help and she had done it. Afterward, she chose to leave the music course because she wanted to give her all in supporting Kanon, which means becoming a school idol with her.
Honestly, that made a lot more sense in my mind.
Also lol, Ren is not her bully back then. The bully's bang was different from Ren's. It would be pretty funny if it was though.