I mean what I wrote, You can mod the centaur, elves and humans to help generate your post. If you need a group of npcs to charge you to help build drama and excitement so be it.

Generic Zero tier NPCs that are used to flesh out a post are moddable by anyone regardless of the author as long as they are not a summoned or faction NPC. Faction and summoned NPC’s have their own rules sets. 

Generic Zero tier NPCs have no inherent value other than to create drama and excitement in a post. If you are unsure about using NPCs ask the poster who has inserted them, if they are nothing more than flavor text you are able to use them as well in any manner that advances your post and the overall story in the thread.