They've only shown other resident kids a few times. A few times that I can think of right off are 1 at the end of 6 where some kids, including a young domehead, are sitting around the same heat vent shown earlier in the movie and listening to a story, and in The Lonely Journey they show some young Maiasaur kids during the ceremony thing, forgot if they gave it a name or not. Not sure if they show any other kids in the background or not.