Solutions
(1) Fullscreen style in manifest (deferred in favour of immersive mode)
(2) Set app as default home in manifest (could also be deferred in favour of immersive mode)
(3) Override back button (could also be deferred in favour of immersive mode)
(4) Immersive mode https://developer.android.com/training/system-ui/immersive.html
(5) Start app on boot received in broadcastreceiver
(6) Draw over nav bar and status bar (handles the one problem presented by immersive mode)