Okay so I've been thinking about additional non-bender roles since it doesn't seem like there will be much of an issue filling out the rest of the roles. I was thinking of a non-bender who serves as the Avatar's bodyguard and has been in charge of safety for a while. Kind of like a head of security. (I hope you all got a funny visual of White Lotus members whispering into their robes 'The Avatar is on the move!' as well.) As for why they're not teaching the Avatar themselves, it could be any number of reasons; maybe they don't want to. Maybe they'd be a terrible teacher. Heck, maybe they WERE planning on teaching the Avatar and are super miffed to meet this other non bender.

And the leader of the resistance movement; the person who sways the Avatar and crew into helping. A strong non-bender who led the people and has a talent for leadership. They could obviously join the group when they decide to stay and fight and continue on with them throughout the rest of the books as needed. It might be interesting for a slightly antagonistic introduction to a character as well.

Let me know what you guys think about whether or not you'd be interested in some roles like that!