MC being flustered at Risa-chan during bathing incident, trying to control herself lol...hopefully MC didn't change the bathwater lol~...I mean MC can always add more hot water, filling the bathtub with new water takes too long. Good thing Risa can still feel sense of touch, seems only her sense of taste has become a little dull and numb.
MC has neglectful mother while Miya-chan has a crazy obsessive mother who keeps her locked up in her room (Went crazy probably from father's death, assuming she was already crazy and obsessive to begin with)
...They both can bond over their crazy horrible mothers [Assuming MC doesn't kill her on sight first (Miya-chan going to need a disguise to seduce MC first to have a chance to join the possible(Low chance) a poly-relationship)]
Let see if MC's mother actually develop morals and conscience (Unlikely but anything is possible).