I have the name of 2 McDUFF's, who came from the British Isles, during the 18th Century: Daniel and Charles.
Daniel McDUFF (1757-1831), a captain, son of Thomas McELDUFF.
Charles McDUFF (c1762-1834), son of Peter McDUFF and Hannah RUSSELL, who came to Canada around 1780, probably as a british soldier (or mercenary) during the American Revolutionary War (1775-1781). He married a french canadian girl, Marie-Angelique MOURARD-LAFORME, in Cap-Sante,QC on Jan 30, 1787. His descendants are well established, in Quebec, Canada and USA. Peter and Hannah had married in St.John Church, in Limerick, Ireland, on Sept 9 1749.