Creating AppleIDs for your kids through Family Sharing and using those AppleIDs on those devices would solve this. You as organizer can view and manage all devices; all purchases are paid through your account (but are tied to the purchaser), and you can set restrictions and require permissions for many activities (including in-app purchases). Plus, all the bluetooth devices remain per-user. And it keeps your stuff out of their stuff and vice versa (though selected items can be shared).

https://support.apple.com/en-us/HT201088