If you can explain to me how any of these songs deviates from the absolutely average, I'm willing to listen.
I listened to each clip this morning and promptly forgot them all. And I have a penchant for picking out something to remember, like or dislike, in everything I hear.
Well... Not the person you were talking to, but, from what I can remember from each (as I'm not listening to them at the moment):
Ranko's song is intense and gives off an occult feel or something.
Miku's song has the really cool saxophones in it, but is otherwise plain.
Kirari's song is nondescript, really, though there is a sense of energy in it.
Mika's song is... also nondescript.
Uzuki's song is refreshing and slower than expected, though the Gratuitous English of "Smiling, Singing, Dancing All Night Long" reminds me of a Haruka song.
But I may have a bit of bias, as well. Here's hoping the full versions are better than what the samples are telling.