You shouldn't in principle need to worry about the difference between the sdl2 and pygame/sdl backends on Android, since kivy's own API is the same in either case.

You don't need to install pil either (kivy preferentially uses other providers), unless directly using it in your own code, in which case you can include it in the android build by adding it to the python-for-android modules string or buildozer requirements line (just 'pil', this is the name of an internal recipe). If you have a window and text provider problem on android, that indicates that something is wrong with the android build, and we can help to debug if you provide the logs. I'm not sure offhand what problem would allow the android build to complete but give this error, but it would probably be revealed in the log.