Wonderful post, some great ideas here. Children are a wonderful gateway to sections of RP you haven't experienced before so its a shame to see people fall into the edgy orphan trope. If you are RPing with a child as a parent or close companion, give them things to go on, just posing some more mundane situations can really help flesh out their character significantly and be a lotta fun in the process. Don't go around adopting a child on a whim, that player is expecting some commitment on your part to some rp regularly, not just a chest in your house.