So, it's been confirmed that children can't be killed. However, everyone else is fair game.
I wonder how the AI of the children would play out if all the advlts somehow "disappeared". Would we have a Lord of the Flies situation on our hands? Would the children go out and hunt for food? Would they form their own society?
I can just see them pushing a rock over a cliff like the bandits do on the one that looks most like Piggy. They've probably seen to it that some of the advlts are essential in each hold so that doesn't happen.
Also, don't be surprised if your thread gets merged with http://www.gamesas.com/index.php?/topic/1227045-children-in-skyrim-restricted-discussion/page__st__80__p__18598679__hl__children+in+skyrim__fromsearch__1#entry18598679.