The only new stage I think that's playable is that new stage for Neko Arc. I can't be sure unless anyone actually picks her, which is never going to happen.
In story mode, if you make it to Warc, you fight her on that new stage of Arcs, which is just a minor edit really. So you haven't seen that in the matches huh? What's Warc's stage anyway?
And I'm pretty sure that the new highway stage is just for story mode. You fight a lot of different characters on that stage depending upon your character's story. It's nothing special way, since the music sucks on that stage. :p