Just beginning in-dept research on Duignan side of family. At first reading it appears that your question might lead to a connection, but too early to tell. While I look into it further can you send additional information?
My greatgrandfather was Patrick Duignan DOB abt. 1846 Mulingar, Co. Westmeath, DOD 12/30/1896 Mulingar. He married Mary Kenny in Argentina abt. 1850. He died on trip back to Ireland. Mary Kenny and 5 children returned to Westmeath. My grandmother Catherine was one of those childred, DOB 1/12/1881 in Chaomus, Argentina, DOD 5/1/1974 NYC. She married Edward Williamson Doherty, my granfather and they had 3 children; his son Willian Edward DOB 9/9/1909 NYC was my father and had 4 children. I'm Peter Francis, 2nd born DOB 2/21/1940 NYC. At 1 yr old moved to Atlanta. Grew up & educated in Atlanta.