^^ I don't know all the details but Nijigaku is a spin-off while Superstar is intended to be the actual next gen. Something along those lines, sorry if this doesn't help.
It's pretty much that, yeah. The nijis weren't initially going to get an anime at all. But who knows, maybe they'll get more. God knows there's material enough.
Shioriko...
@Aquwin I agree it wasnt really that tangled- (though you did leave out Asami from the triangle they were first in)
but I also agree with Bean that I wish this is what happened- i.e Korra fell for Asami a lot earlier and they coulda been a couple during the actual show rather than just right at the end.