As a result of their young age, the children have little role in the affairs of the adults. Many are free to play and run around all day, though some are used as inexpensive labor for some of the simpler tasks.
Interactions with the player character
This character has no special interactions.
Children offer a bit of random dialogue.
Note that their relative insignificance doesn't mean they are irrelevant. Killing children is a heinous act and the childkiller is nearly universally reviled. The player will only be branded one if they kill two children. One is fine.