To fully utilise what you want, we’d need fully implemented interactive signage - Interactive Signage
but that will come with 1.9 series.
For now:
Windows clients, it can function as a screensaver displaying the content, then once something would be pressed it would ‘wake up’ the PC, which means you could have your browser in kiosk mode running there.
Alternatively, if you open status window (press ‘i’ on your keyboard) then Xibo player will no longer be always on top.
Android clients - you’d most likely need to use SureLock Kiosk Lockdown or similar