I read your original post and some of the others. I know a thing or two about southern South America and Tierra Del Fuego languages.
But if I was to do this, I would maybe base it off of "At the Mountains of Madness" by HP Lovecraft and "The Rime of the Ancient Mariner" and "The Narrative of Arthur Gordon Pym of Nantucket". More within the realm of reality, I don't know if Antarctica was ever inhabitable within the last 3 million years that homo sapiens and possibly comparable hominids existed. But at one point, I think it was not at the South Pole and instead was somewhere warmer and has fossils to that effect - under miles of ice.
Whoever told of the Maori legend of a discovery of Antarctica - thanks a lot! I study things like that quite a bit, myths, legends, etc.