Yes, Avatar was a thing way back in 2009. Mainly because it ushered in a new era of 3D. Wow, feels so long ago already....almos feel like we need to explain to the kids how we old people had 2D blockbusters...
But Avatar is not character driven. Cinderella is not a thing without her. But not Avatar. It doesn't matter no one can name a single character. On the contrary, more's the better. WDW could build an entire AVland without a single character. The central element of Avatar is the exoplanet, the alien lifeforms, with their bioluminescence and interconnectedness. This aspect is remembered by everybody who's seen it.
And even if they don't, or have never seen the movie in the first place, that doesn't matter. IP doesn't make a Disney park, or else all of the criticism of the fanbase the past 15 years has been mistaken.