When do you think Sakiko will realize her prophetic powers? She clocked Nyamu ahead of time too.

Uika should start a rock band and call herself "Hatsune". Every interview she has a new embarrassing sibling story to tell. Sometimes they are about "Uika" but other times they are actually about Uika. At some point she tries to replace "Uika" as a member of Sumimi.

It also shows that they each have a lot going on. They can share so much and still be distinct.