Go low tech, use libreoffice or something to make some card layouts, populate the fields from the CSV with a mail merge, print them and pin them to a wall.
This probably avoids an IT call because you should have these things already available.
Hi from … something
You also cannot blame parents here. Most of us live in societies where a 13 year old can walk home from school on their own, and if they buy cigarettes, alcohol or visit a strip club then the business owner is in trouble. Business owners should figure out how to provide their products safely.
You cannot. Any platform with somewhat private communications and kids will have predators on it.
I feel like there should be an “are you alive” federation activity in activitypub, as well as an “I’m back” activity.
Servers go up and down enough that maybe it should be part of the spec