>It specifically did.
It did not. Roku only says:
"The Ocean and the Moon are ancient spirits. They crossed over the Spirit World to the mortal world very near the beginning. There is only one spirit I know of who is old enough to remember."
>No it isn't.
But it is. The animals teach bending, the Lion Turtles give the power to manipulate the elements.
>In Avatar it's hinted to have been gotten directly from animals
That's your headcanon. We're only told that people learned bending from them(as in, the specific martial art. Like the Dancing Dragon for example is something the Dragons taught humans.)
> and when the moon goes kaput waterbenders are helpless, that doesn't make sense when it's a gift.
It does if we simply make the assumption that the Power of Water is spiritually/cosmically tied to the Moon and Ocean spirits.
>And crossed over.
"I lived ten thousand lifetimes before the first of your kind crawled out of the mud! It was I who broke through the divide that separated the plane of spirits from the material world!"
The implication there is that he created the spirit portals. But as we've seen Spirits can cross over into the spirit world without any sort of portal, so there's no issue here. Tui and La are simply like Hei Bei, Wan Shi Tong, Furry-foot, Bum-ju, and all the other spirits in both shows that can cross between the two worlds.
OR, Vaatu broke the divide near the beginning, and Tui & La were just one of the firsts to cross over after he did.
>Which humans used to bend. By watching animals, they learned to bend better.
"bending" in this context refers to the actual martial art, which the humans did not learn(besides Wan) for at least a while.
>That are completely unlike anything we see in TLA,
Nope. TLOK just introduced more Koh-esque spirits
> which were feral extensions of nature
What do you even mean here?