America has always been a Melting pot for crying out loud. There were people in South America of Polynesian, Chinese and African descent before Columbus even landed.
In North America there were the people from Asia who came over the land bridge, there were some Caucasian looking folks on the great plains and even some people with Greek blood in them in the Caribbean.
One group always supplants another, such is history.
I’ve not heard of most of those things you mention........
.. not saying they’re not true, just haven’t heard of them...
True. But the popular notions are the ones that usually get top billing even though most know the truth of the matter anyway.