Don't hurt the NPCs. That's one of the rules of the SSS. Even if they're not human we don't know exactly what they are, so it's better safe than massacring an entire classroom and trying to figure out if you it was really okay. They usually won't harm anyone, so there's no point in harming them back.

[ Yuri smiles. ] Haruhi can play pretty much anything you put her on and sing. Leon claims he wants to be a rockstar, so you could try training him at least. I have experience with bass but I don't play anymore so you're out of luck there. [ actually she just sucks and got fired so she didn't bother to continue practicing. ] I'll find you more members as soon as I've got them.