Tower of Fanatics Warp

You could, alternatively, change the Magimaster battle event to do 1 of 2 things:
1. Offer you a dialogue box with a chance to warp to the bottom.
2. At CC/5583, it reloads the roof as a shortcut to get rid of all of the NPCs. You could change this to instead place your party at the foot of the tower.

One other possibility is just to edit the Warp subroutine, from CA/0108 to CA/0153. At CA/0138 and CA/013E, there are "special handlers" for warping out of Kefka's Tower and the Phoenix Cave. clearing all of your parties and setting Setzer as the lead character. (Note that the Phoenix Cave one is fully functional, but dummied out because the Phoenix Cave maps have the "can warp" flag unset. Setting those flags will allow you to warp out of Phoenix Cave.) You could add another check in here that checks for the event bit that replaces the Fight command, and have a special warp subroutine that removes that bit (the hex to remove that bit is "B9 38"), then places you on the world map. Actually, there would be little harm in just adding B9 38 to the subroutine in general, as there's no way to be somewhere OTHER than the Fanatic's tower with it set.

EDIT: I tried the method in the 2nd paragraph, adding "B9 38" to the warp subroutine, then enabling warp in all places of the Fanatic's Tower except for the roof and gem box room. It worked. It required 7 bytes of free space in the event blocks (CA-CC) though.