I don’t know if you’ve read Hawaii by James Michener (I recently re-read it), but the way he lays it out is it the existence of the Havaikii Islands was probably a legend among the Tahitians as they would go very very far in their canoe ships (catamarans). He speculates that if they could have gotten close enough they would have seen a star in the sky right in the same place, always on the horizon, and it would have been Mt. Kilauea, because it would have been very active in that era.
Thank you! I read that many years ago and can’t remember much at all.