While researching my wife's side of the family tree I came across your 1999 posting on Ancestry regarding an Anthony Duffy and Ann O'Hara. It mentioned that Anthony may have been an Ambassador to Australia in the 1800s.
A little more searching on the Internet came up with this message which leads me to believe the people you mention are my wife's great-grandparents and above.
My wife's paternal grandmother was Dorothy Duffy, and I recently found her parents' marriage certificate in Iowa. Their names were Michael Duffy and Josephine Bernemann, and Michael's parents are listed as Anthony Duffy and Annie O'Harra (sic).
I had also made contact with someone else researching that part of the tree who mentioned (along with my mother-in-law) that Michael was in the Merchant Marine and died in Finland. (They end up back here in NY later in the census.)
I realize the messages I found online are fairly old, but hoping a notification goes out for this response! I'd love to share notes on the family (and hopefully learn some more.)