ooh ok let me chip in with my thoughts:
tara: i think airbender is the obvious choice because of ‘in another life i could fly’ and dancing being linked to freedom for her (‘artistic abandon’)- plus she’s canonically an air sign. but i can see the waterbender angle too, especially with the focus on community- her trying to keep everyone together reminds me a bit of katara.
kat: i’m thinking maybe waterbender because she’s easygoing on the surface but there’s a lot of turmoil underneath, which makes me think of the changeability of water. but there’s definitely a wish for freedom in her which could correspond to her being an airbender. i could also see her as a non-bender because of her complicated relationship with dancing; and because i think she has an insecurity about not feeling ‘special’, especially in comparison to tara, which could tie in nicely with a non-bender’s character arc.
abigail: i definitely see the vision for her being a firebender- determination and ferocity and all that. in some ways i think she could actually parallel zuko, in terms of being pitted against the ‘naturals’ and trying to make up the difference with sheer force of will and commitment. though i could also see the case for earthbender because of her tenacity.
sammy: i can see the non-bender angle, but honestly i’m leaning towards waterbender- mainly because of the focus on community. his speech in s2 about the group needing to be there for each other comes to mind.
christian: he’s a hard character to pin down (especially given how frustrating i find him most of the time 😅). but i agree with some of the logic behind firebender (though i don’t think his character development was nearly as well written as zuko’s). he’s definitely driven by internal conflict lol.
ben: i can honestly see the case for any element (he’s canonically a fire sign and has the passion for it, and he has the steadfastness of an earthbender) but i think it’s ultimately between air (he definitely has some similarities with aang, especially his resilience and narrative connection with hope) and water (he’s also very narratively connected with healing, and is very adaptable).
ollie: i can see earthbender or firebender, but i lean towards firebender because he can sometimes get carried away by his ambition- and because of that might lack the steadiness of an earthbender/be driven more by passion.
ethan: i agree with him being a non-bender, the reasoning is spot on. the parallel between the relationship with the body in dance and the relationship with the body in bending is really interesting- actually provided me with a lot of the framework i’ve used here in analysing the other characters too!
grace: firebender. her being the most ‘natural’ dancer reminds me of azula being said to be ‘born lucky’ (though azula’s perfectionism is more reflected in abigail). and she’s definitely driven by impulse/passion- though she can also be very calculating. i can see her being a lightning bender, actually.
as for the avatar, grace makes sense in terms of sheer power, and again her being the ‘natural.’ but i think in terms of the avatar’s spiritual duty of keeping balance, it makes most sense for it to be tara- tying back to her being the ‘glue.’ could also be sammy for the same reason.