AUS YES GOOD
School plays are a must for high school AUs, haha, especially with characters like Nezumi, that's just asking for it. I like @Vox's idea of Shion rehearsing with him and then accidentally ending up on stage! He'd probably be pretty good too after all that practice.
Ahh, Safu! She'd likely be top of the class, Shion a very close second (or he might start slacking a bit after meeting Nezumi, hmm...). I do love her friendship with Shion so that'd be nice to see in a less - eh - No.6-esque school setting, lacking a better word. Totally with @AoYokai there, haha.
So like a school where they do get to express themselves. Maybe Safu would actually be good in arts? Painting or writing? I'd imagine her art being pretty bold compared to what people might expect when they first meet her.
Ah, Inukashi would not be pleased with this school thing, I imagine... Probably might need tutoring. Hm-m. Yep. Study group? All four of them? <<
Nezumi and Shion meeting, hm... my first idea was that Shion would be class rep in charge of taking care of the new student, but I'm fairly sure there are 50 fanfics like that already, haha. I do love Nezumi and Shion showing each other their own ways as @Aoyokai suggested, that's very nice!