If Kyou is Hajime’s sister, I wonder if it’s fair to assume Kyou is either dead or dying hence Shiho’s intense conviction of being the best before Kyou’s passing or before she passes, leading to her disliking and leaving her former band due to their distractions with love and etcetera which set them behind from what she wanted them to achieve before she thought it was too late.
We also know that Momoka knows Kyou so if she is/was in love with Kyou a lot of things would make sense on her end, and also tie all of the 3 members back together to Kyou.
