I had heard of these people, but not these detailed stories.
Possibly they are true, but bones do not lie! Sinbad recalls the Roc and valleys full of jade and gems. That was his rendition of what we now call New Zealand at an unknown post fluvial time.
Undoubtedly, we will hear more.
Cannibalism is a method of altering the human species, with tragic consequences for the victims. I do not encourage it, but your mileage may vary!