Just something crossing my mind during a midnight shower:
In the first Avatar movie we met Na'vi of the forest. Very earthbound ones. In the second movie we met ones deeply connected to the water. The third movie will be literally called "Fire and Ash". Furthermore it was revealed there will be a traveling trader folk (nomadic?) who fly with floating creatures high up in the air: https://cdn.kinocheck.com/i/oxid3emrch.jpg
Honestly, the concept of the five elements is very prevalent in both Eastern philosophy and even in some Western ones like Wicca. The pentacle represents fire, earth, water, air, and spirit (usually at the top of the star), bound by human will (the circle). The Dresden Files explains this multiple times and I think the meaning is actually true for practicing Wiccans based on previous experiences I've had with some. Avatar: The Last Airbender goes with three of the traditional Chinese elements, adding Air to Fire, Water, and Earth, but omitting Metal and Wood. Oddly, Pathfinder keeps all five and ADDS Air for their Avatar: TLA inspired Kineticist class' Elemental Gates, and those are gates to the Elemental Planes that kind of surround and infuse and make up the Material Plane where everyone lives.
It wouldn't be strange at all for JC's Avatar to follow a similar pattern with the four elements you listed plus Spirit (which was also an element in TLA but not directly controlled except by the Avatar) representing Eywa and the spiritual connection that goes beyond simple things like connecting your nervous system to a glowy manta so you can breathe underwater. (yeah, that's simple compared to the more esoteric stuff in the movies for those who don't know!)
Honestly, the concept of the five elements is very prevalent in both Eastern philosophy and even in
"We had a peaceful planet... then everything changed when the fire nation human race attacked." Lol, I seriously think you should stop using that menthol shower gel.
"We had a peaceful planet... then everything changed when the -fire nation- human race attacked." L
