No Captain, as a fellow Canadian you will know that you will not find a single Inuit in the world, much less a trained actor, that has a beard. The "races" in Avatar have been mixed right from the beginning, there was no "racial purity". If you think maybe you'll put a bearded Chinese in place of the Inuit, then I don't see what the heck difference it makes if you put an Italian or Spaniard. The whole actor/race thing is a red herring.
You can claim all you want that the writers did tons of research (and I agree they did) but can you point to a single thing in the Northern Water Tribe culture that has anything to do with Inuit culture, please? They sure as heck don't do Tai Chi up there.
The martial arts in the show are authentic if you're talking about commercial late 20th century versions. As far as anything that was practiced in the 18th or 19th centuries, no it's not authentic. And yes, I've done 30+ years of training and research to say that.
I don't know bugger all about Tibet, but my friend who is Tibetan does, and laughs at the depictions.
The cultures are researched as much from pop fiction as they are from any actual academic history or anthropology. Or I suppose you think Crouching Tiger, Hidden Dragon was a documentary?
I love the show, I love the writing, I love the amount of creativity that went into it. And the creativity went into the design of the nations' cultures as much as anywhere else.
If whitewashing the film doesn't bother you, that's fine, I suppose, but it's symptomatic of a much bigger problem in Hollywood.
Whatever the problems in Hollywood are, they have no problem finding Asian actors, whether for large scale movies or TV shows. The "whitewashing" is purposeful IMHO exactly so that they aren't accused of racism in depiction certain nationalities in as bad a light as they do.