Here you have a few suggestions.
For... well, pretty much anything. I just think this is an awesome song that needs battle usage:
http://www.youtube.com/watch?v=fggOUrvGwdo Just like this:
http://www.youtube.com/watch?v=SOuLkMznbgoThough I'm not sure for what I guess this could also be used as a battle theme too. For some reason the Student Council Leader came to mind, though I suppose that depends on the type of person that assumes the role:
http://www.youtube.com/watch?v=eYr16eL_lT0 Either that or this:
http://www.youtube.com/watch?v=ul1SZFBOc4sI also reckon that this could be used in fights against either Shadows or Daemons:
http://www.youtube.com/watch?v=0nX_G8aj-vc Maybe it would be more fitting in DDS, however. That's the feel I get from it.
Now, apart from battle themes...
I think this would be great for Yamaeshin South, seeing as it appears to be quite a remote location:
http://www.youtube.com/watch?v=ix38fnllF3Y This one could also be useful for any quiet area of town:
http://www.youtube.com/watch?v=f8Akx9TRiUE Though, I'm having some difficulty finding town music because I'm not too sure about the general ambience. I'm guessing it will be somewhat like in the most recent Persona games, in which each area has it's own theme until towards the end when each song changes.
If the Student Council is as evil as they seem to be, then this is probably perfect for them and their apocalyptic ways:
http://www.youtube.com/watch?v=ocfxVwsiKvwFor now, that's all I have, though I'll keep looking. More than likely they will almost all be from games, if you don't mind.