I always recommend that things like light switches and lamps work completely normal. That is, no need to use a phone, voice assistants, or tablets. Having smart switches or buttons that mimic normal switches is always best for visitors and guests.
You could do this either way. The stock Dashboards can be per-device, you don't need the Hubitat app, you can use a direct URL for this particular device.
For 3rd party dashboards, many users like the Hubitat Dashboard for Android by Joe Page [RELEASE] HD+ - Android Dashboard
for this, but there are built-in options of ActionTiles and SharpTools. I haven't used any of them so I have no opinion which is better.
I am not sure why exactly a tablet would mind that? Some devices might not like that, like a cable box or similar, but tablets and phones are connected and disconnected all the time.
When I tried out a wall-mount tablet, I put it on a smart plug that was activated by motion, and turned off after a period of inactivity so the tablet wasn't just plugged in charging continually. I also used the option to "keep screen on when charging" and (I can't remember how exactly) disabled all passwords so the outlet being powered brought the tablet to the home screen automatically. I think many usually use Fully Kiosk as a way to automate that process.
