I have been playing for a short time, looking at all the items the mod has, and I haven´t seen a way to spawn benders like you could spawn villagers or animals. I want to make a world and build villages there, and I´d like to place benders in them, but I don´t know if it´s possible.

You should be able to spawn them using the /summon command. Tab-completion should help you figuring out their identifiers.