The Mini itself is easy to use this way, just get a 14500 cell and short out one of the AA slots with a small wire.
You can stick the 14500 cell right into the Mini Remote without further modification.
You can even use a 4.2V li-ion or 3.65V LiFePO4, I’ve used both and they seem to work fine, as long as it’s a 14500 size. The LiFePO4 dies abruptly and the li-ion gives a bit more warning.