can you keep kids in a room using the lock doors thing" and can parents get in when it is locked

I have a hack which was not letting my doors lock properly anyway, but there is an option to lock the door to ALL sims. That would include kids, wouldn't it?

Yes. It traps the sim inside. Wonderful tool for murder. But, if you lock a toddler and child in the room and don't interact/feed them or let them sleep the social worker will walk right through the door and rescue the child. It does work well short-term for keeping toddlers from roaming about the property. Mine are kept so busy skilling, they don't have any time for roaming. I'm a slave driver. *cracks the whip*