this is a really stupid suggestion but, for the FRLG arc why don't you do "through teh fire and flame"? Blue's parent's were so far away and all that and red and green had to keep working harder and whatev. doing a romantic song for RS arc would kinda give it away wouldn't it?
yeah, i'm kinda negative today. RGB was like the first, so it could be like a song that was the first of its kind, yeah, beat me.
romantic songs? i suggest cascada or taylor swift, but mayybe that's a little too romantic...