I recall that my step-father's parents claimed Seneca Indian from Upstate NY in the heritage. My own research shows nothing of the sort. English all the way back to Connecticut. And, yes, a lot of people claimed Native American ancestry that was not there. You may be exactly right as to why.
I noted an error in one statement about when "whites" were in VA. I am descended from Stephan Hopkins who was at Jamestown in 1607. Being that he was from Eastern England, I would presume that he was "white". His wife and children died during the famine, he went to Bermuda, thence back to England and met up with the Puritans in his native area of England and came back to America in 1620 when the ship was blown off course to Plymouth on the way to Jamestown. Or, so the story goes.
A former love was from Logan, W.VA. and was quite dark. His father was Czech and not sure about his mom, but she was also quite dark and on reflection could've been Melungeon. Don't recall her maiden name.