About Cape Reinga and Hawaiki: it is astonishing that there are found many similarities in myths around the world, of peoples that have had no connection with one another. This story of the ancestral spirits departure to a mythical home makes me think of similar in Norse Myth (Folkwang).
Not isolated, I found similarities of this kind in Native American and Traditional Siberian communities as well. There, one could possibly cite the Bering Strait Theory, which Native Americans vehemently oppose: Native Americans Call for Rethinking of Bering Strait Theory.
But there is no such tenuous connection between Vikings and Maori, other than perhaps they were seafaring people.