Just saw your old posting, probably have your answers by now Just in case, My gr grandfather was Thaddeus Cooper. His father George( my gr gr grdfth)was married first to Sarah"s sister Agnes (Nancy). Strange doings followed leading to George and Sarah leaving N.Y. and starting anew in Illinois.
Sarah and Agnes were the daughters of Peter McAuley b 1770, of Cavan Ireland and Lady Janet Dawson (allegedly) They fell in love and eloped to America, married onboard ship. Janet was disinherited by father, Baron Thomas Dawson(allg.) She had enquiries made later in life about possible inheritance but all mention of her had been " removed as if cut out with knife".
George, and I think first wife Agnes named one of Janet's grandchildren Thomas Dawson Cooper, so something was strongly believed at the time.
Am trying to track this down , will post as more comes to light ,Ralph Cooper