Apparently, I was wrong.
So, I was wrong when I assumed that Ms. Transracial's parents were telling the truth about "Native American ancestry" - I should have known better. Anyone who would adopt Negroes would, I guess, be prone to desperately search for any hint of non-White ancestry in their own background. Next time, I should just assume maximal White freakishness.
This though leaves the "movement" with the options of either focusing on "Asiatic Slav" ancestry or "altruistic high-trust hunter-gatherers." Or, to hold out hope that there is a taint of "Med" there. Problems, problems.