Watch, I think, the second Spy kids movies. A whole bunch of kids with huge jars filled with dollar bills . And yeah, kids can either sell you items, or you can do quests for 'em.
Ok that's true. But that would have to be one AWESOME teddy bear to convince them to crack open the quarter jar.
I mean yeah sure diversity is nice, but it's really unnecessary. Then you have to go through the work of making the children invincible and all that.... or you could just let us kill them!
Pretty much any screenshot where you see characters that aren't player controlled are NPCs. Like in this one: