This is kind of an old post already, but there's a mod out there that implements a mode that allows you to manually control all your teammates, and it does so by changing who the leader is after every turn you take, so I assume that a menu option (or even a toggle using some key combinations) to permanently swap your leader in dungeon could work, unless there are some caveats I'm unaware of. There's also this new ROM editor, but I haven't checked that out yet and I don't think you can use it to implement such complex functions that don't exist in the game yet.
This is kind of an old post already, but there's a mod out there that implements a mode that allows you to manually control all your teammates, and it does so by changing who the leader is after every turn you take, so I assume that a menu option (or even a toggle using some key combinations) to permanently swap your leader in dungeon could work, unless there are some caveats I'm unaware of. There's also this new ROM editor, but I haven't checked that out yet and I don't think you can use it to implement such complex functions that don't exist in the game yet.