I took a 23andMe ancestry test and it genotyped me as being Duffy Positive Antigen for blood typing. I am NOT resistant to Malaria (somewhat) even though I am heterozygous Duffy Positive. Most African-Americans and Africans are Duffy Negative. Although, I'm African-American, I'm NOT Duffy Negative, but Duffy Positive for the Antigen.

Does this prove I have Native American ancestry? I read on the internet that those of European and Native American decent are Duffy Positive with the Duffy Antigen, like what I have. Could this dna result prove I have Native American ancestry, in addition to being O Positive Blood Type also that many Native American are O Positive Blood Type?

A group photo of their tribal council (2013 Legislature) has these names:
From L-R Front Row:
Katie Case,
Dean McManus,
Connie Barker,
Shana Tate Hammond, and
Nancy Elliott
Back Row L-R:
Mary Jo Green,
Scott Wood,
Toby Perkins,
Steve Woods,
David Woerz,
Tim Colbert, and
Beth Alexander
Not Pictured: Linda Briggs

So, unless they imported white people to rule them, which I doubt, most of them have English surnames. (McManus is Scotch) As others have said, Native Americans didn't have surnames. Before they converted, they didn't have Christian names, either.

I'm a Chickasaw Indian and my last name is Davis, I'm getting my last name changed for personal reasons and was thinking about choosing a Chickasaw surname

You probably can't. But if that info about relatives includes names and relations, and they were alive in the USA in 1940, and the name is relatively rare, you might be able to find the person on the census.

If the state of birth is different from the state of death, and both are sparsely populated, you might be able to find a list of likely candidates on the LDS site.