Average 2017 with Oneplus 3T (snapdragon 821).
Latest ScummVM hides system cursor on Android 7. I tested this with my Oneplus 3T and the black cursor is finally gone. So black system cursor can be hidden for Android 7. Perhaps you can now do the same for Magic Dosbox?
My vote for option #2 as well. It sounds much easier to setup.
I wasn’t able to do what you suggested. I could remap the keys but I couldn’t find a way to turn the mapping on or off. Mapping alone would be enough if it could catch key combinations and turn them to single key press. Unfortunately that was not possible either.