I think only Dragon Slayers who haven't finished their training can fall without being killed. There's a puzzle where many people have clearly fallen to their deaths, including Slayers, I think.
As for kids: yeah. This is another reason why a dev kit is sorely needed. From Children of Morrowind onwards, parents have been getting together to add kids into games, to make them seem "more real" to them.
Seeing kids in Morrowind balancing along the city walls, fighting each other with wooden swords, playing tag, and gossiping about kidstuff made the whole game suddenly come alive, for me. Vanquishing a great evil means so much more in a world where there are children to protect the future for. If I were writing a "Children of Rivellon" mod, I probably WOULD have a child slain by Damien's actions, but the mother or father survive. I'd probably make it a baby so that the parent could be still clutching the sorry bundle: maybe not have it dead, but have it coughing, on the edge of death, and the player unable to help (since there are no anti-poison potions in the game, I think). Depending on the player's approach to the character, they'd either exhort the player to slay Damien to revenge their child, or curse the player for causing Damien to attack.
Another reason children delight me in games is that they add a whole 'nother dimension to moral quandaries.
If one of the five "ex-dragonslayers" were a child, or had a child, would you so easily mow them down? If the slayers' camp had children in, training with wooden swords, would you so easily wade in with sword drawn? If the Red Hand goblins had children in their village, would you be more inclined to take back the fake head instead of the real one?
Richard "Lord British" Garriott totally "got" this with the later Ultimas, and made sure to include killable children in all of them, in some form or another, after people had attacked him for "forcing" them to kill children at the end of one. His response was that personally, he'd just cast Sleep on them, and walked past. All the Fallouts have included children, though F3 made them non-killable.
Non-killable children are not a moral quandary: they're a forced outcome, so aren't nearly as interesting.
So, if I were modding in children, I'd make them 0 XP. You get no bonus for killing them, but no penalty either, beyond the reactions of those factions who become hostile for killing them. (Plus, modding in 0 XP mobs is less of a danger to game balance, of course.)
