Is Prince Charles Edward Stuart an ancestor to Mary Queen of Scots?
Descendant, not ancestor He was her 3 times great grandson. Charles Edward James Francis Edward James II\VII Charles I James I\VI Mary (I) Queen of Scots
Contrarywise. Quite the reverse.
Yes. Charles Edward Stuart was was the elder son of James Francis Edward Stuart, grandson of James II and VII and after 1766 the Stuart claimant to the throne of Great Britain. James II and VII was the son of Charles I, who in turn was the son of James I and VI, Mary, Queen of Scot's child. https://en.wikipedia.org/wiki/Prince_Charles_Edward_Louis_Philip_Casimir_Stuart
He was her great great great grandson. King George I was her great great grandson.