Some of these names are close. I see a Henry Mckee (might be a John Henry?) as one of the sons of Thomas Jefferson? Did you say you knew John Henry's mothers name?
I have alot of charts and a family history (my side) thing for the Mckees. If you would like I could scan it and email it to you? I have not looked at this stuff for years. My job makes it hard to research anything.
I also have a newspaper clip of J. Edwin Mckee who was the Post Master General under Truman.