Arch linux? :) joke aside perhaps something with btrfs support is handy. you can easily rollback if something breaks. For parental control don't give the kid sudo/root. other then that restricting websites and stuff is more easily done on a firewall outside of the kid its control.
Almost any of the larger distros will suffice i think. Personally a fan of opensuse tumbleweed which has btrfs support out of the box. use a DE like kde/gnome and i think you have a very solid start
IPA beer is good for sure. freeIPA is a central way to manage Linux devices. manage users ssh keys and even limiting sudo commands with sudo rules. and some other things. It can not do everything active directory does but their sure are a load of similarities.
X11 is very old and all code has been glued on over the years. It is one big spaghetti mess. Very hard to work on and fix bugs. Wayland is much more modular and future proof.
Anyone has recommendations on where to find information on who to vote for for the European parliament elections?