To be honest, I know more about medieval English monarchs and 20th century ones than I do the 18th century ones.
Maybe np can help out.
That patently ridiculous TRIPE about King George III's wife, Charlotte, being part black is utterly, unalloyed, complete bovine excrement; not to mention the fact that it is a very recent pile of tosh!
And the screwy report, trying to make Charlotte part "black" is even MORE distant than that of Fauxhantas' "part Cherokee" ancestry; if it is even remotely true. :-)