I see. I personally have not used the ‘person’ functionality in HA.
I do use these custom-variables custom_component often: Set variables, custom component variables
It allows you to define and then set variables (who’s status survives reboots) via script.
You could essentially build a variable.kids_home and set it to either home or not_home based on the triggers you’d like?
I will say, triggering based on door open / closed could trigger false-positives quite often. Having kids myself, I know they’re always opening the door when friends come over, to go get the mail, etc. Anyhow, just my $.02.