As for the "genre" part, you ask for the genre of the original track, or the remix itself? What if I don't know in which category the original track falls in, can't be enough by just listening to the track ?
Another question: what if I'd like a remix of multiple tracks, or does it have to be from just one?
As I read my own questions, they may sound pretentious, when I'm actually just curious in how this exactly works, as I listened to the radio and heard a remix of two tracks. Not sure if this is done voluntarily by the remixer or if it can be actually requested.