oh man people definitely overuse the word foreshadowing
especially when it comes to those new disney tv shows
gravity falls was full of great foreshadowing and now everyone who watches owl house/amphibia/star/etc is like "this is clearly foreshadowing!"
probably some of that going on here too
I prefer the zonai to something like the twili because of this. The twili have no impact whatsoever on the lore, they could exist or they could not and things wouldn't be any different.
I like the idea that the zonai, or the picori, or the wind tribe, or whatever, have been hanging around...