Ask HN: Best way to manage a fleet of iPads in a “hostile” environment?

My aunt owns a children's dental office and they have a bunch of older iPads out in the waiting area for the kids to use while they wait. The iPads keep getting messed up so she asked me to fix them. Here are the constraints:

1) They are used by other people's kids so they should be content restricted

2) Older kids are mischievous so they should be protected from them too.

3) The staff at the office isn't very technical so adding apps and refreshing the iPads needs to be very easy

Pointers towards apps or write-ups would be appreciated! I tried Google first of course but couldn't find any really good recent info -- everything seemed to be years out of date and suggest apps that either aren't maintained anymore or are only available to education.

Thanks!