The mustang EFI does not care what accessory drive is in front of the engine. You could run V-belts, Mustang serpentine, or Explorer.
Do you still have the original Bronco V8 engine? If so that is probably your best bet. You can get the correct pulley offsets, fan clearance, and even timing pointers that line up. Any of the venders sell the offset adaptors that keep the accessories in the stock location. You don't even have to change the belt lengths this way.