Expecting that next chapter it will be revealed that Mitsuha named Yotsuha which was already obviously foreshadowed.
It does suck that Fuu would punish Yotsuha for something she had no say in whatsoever... Like my one holdout is still the small amount of possibility it would be Fuu's mother instead. I do have a theory that Kazuha was killed by whoever it was first and then once Kazuha was gone they moved on to Uichi/Yotsuha, though my other thought is that Mitsuha killed her to protect Yotsuha.