EDIT: Yeah, you are right!
Then again, I presume you are reffering to "Suteki da Ne", which although not actually in- game music IS supposedly the vocal piece for this game, which does seem to be "Melodies of Life" in a different language (I think Japanese?), but remixed a bit.
So yeah, I guess you’re right. Somehow.
EDIT: Is it just me of does Tidus’ Theme remind you of Dali in FFIX? Just something about it.