Sure it is, shut down the phone when its "quitting time" and then if they turn it back on, thats ok, internets disabled

For the cellular data issue, you can set a SIM pin so when the device is turned off and on, they need you to enter the pin to access cellular data

How is their commute relevant? If they are WFH, theres less people needing to commute. Thats less fuel or more efficient fuel economy for public transport to use

Honestly, its overkill. When my MaBook went kaput, i had to start doing everything on my iPhone. Had to get a good mobile documents office suite (Collabora is great ), do all my banking with both mobile apps or desktop browser apps, etc. Its been dfine, i doubt i would use a full size computer for that anymore.

Have you ever tried bluetooth wearables like the Bose SoundWear? Off topic but they are awesome