Cheevey

As far as I'm aware, if the songs had been 100% composed by the remixer then all you would need is the composers permission, but these remixes are based on commercial compositions from other composers & publishers so unless you can get permission from everyone who owns the rights to the songs you want to use, it's best to avoid using re-mixes just incase. Even though it's unlikely anyone would complain, not asking for permission is not very polite. Why not ask in the forums if anyone would like to compose and perform an original soundtrack for your game, that would give you something original and possibly even better than the tracks you wanted to borrow.