@mikegnesium he's probably heard of her at best but never met her in person; I doubt he's ever hung out at Kashima's house or whatever.
If anything, I'm surprised Seo doesn't know who she is. Seo left underwear at Kashima's house once for goodness sake
Also this is a good place to clear up the confusion re: the last line. Nozaki's profile being leaked via Kashima = Rei got to know more about about Nozaki from Kashima, not Nozaki's manga career being leaked. The punchline of the page was that Nozaki assumed Rei was a Kashima fangirl who wasn't close to her so he thought he didn't have to worry about revealing himself to Rei, but now we know that Rei can bug Kashima about Nozaki whenever she wants because 1) they're sisters and 2) Kashima personally knows Nozaki.
Once Hori's sibling (I think he had a sibling in the poll thing. Also can't remember whether it was Mikorin or Waka that was an only child. May be both. Also need the other's sibling then too) appears, we might be able to have a sibling centric chapter! Get these wacky-but-not-as-weird-as-their-brothers-and-sisters kids some screen time!
Re: Scanlators' bit at the end. When I was a kid and a teenager, those things currently called "flip flops" were always called "thongs". Then those underwear came out and got marketed, and brutally displaced the term in a year or two at most--you just couldn't call thongs thongs when it suddenly meant thongs.
Around here in my part of the US we still call certain forms of sandals (the ones that go over the front of the foot only) flip flops, and the bit that goes between the toes a thong. Been that way at least as far back as when I was a kid in the 80s.
Hmm. Hmm, hmm, hmm. Maybe. Somehow i've been convinced that they've been hanging out since middle school, but wiki says first year of high school, so it probably wouldn't be weird for them to not visit each other's homes yet.