Random battle theme

Would it be exceedingly difficult to have the Magitek facility background play different music in the WOR (Kefka's Tower) than in the WOB (Magitek facility)?

You can skip ASM code for that and do it by events. There's a WoR event bit, in the entrance event of the map check if it is set and if so use a "Play song" event command with the WoR track ID. I think that would work.

So you are saying that each map (which I'm guessing there are maps for each themed area) have a way to change the battle theme for that one area only?   I have two questions about this method though.  Will it affect the battle background code already in place by the ASM hack, and also, can I figure out where these events are by only hex editing? After all, my 1.1 rom is corrupted and event editors will not allow me to save (consequences of basing my hack on General Leo edition).

Edit: It might be easier for me to sacrifice one of my 4 boss themes in the FF3usME formation editor (the two "current" tracks, the "returners" track, and the "factory train" track), and replace one of them with the Kefka's Tower track - then modify each formation appearing there to use this track.