Patricia,
Archbishop James Duhig was my great uncle. I am the grandson of his eldest brother - Timothy (Edward). As you will have seen from T P Boland's book, there was a sister, Ellen who was a good Samaritan nun - Mother Ignatius as I remember - amd she had no children, I hope.
Other than for the descendents of my grandfather and his two brothers Martin and Patrick many of whom are in Chicago ILL, I have not been able to identify any Duhig relatives. As Fr Boland notes, there is no information on where my great-grandfather, John, came from or his family background.
I am sorry I cannot suggest any connection with your family.
Peter Phelan