Not really sure why you'd need to keybind in your emulator if all of the controls are touch screen.

In general, it should be assumed that everything that is not possible on an original, unmodified Nintendo DS is not allowed

As long as it's not a macro. Like clicking one button and it does multiple things. I am sure it's fine. But the game is all touchscreen-based afaik, not sure why you would need the other buttons.