John Frederick Dauphinee was son of Jacques(James) and Susan Catherine Jolimore, grandson of Jean(John) and Marie Elizabeth Banvard. He was born 11 Sep 1791 and married Marie(Mary) Anne LeJeune. Their son Jean b 1825 married Adele Gaudet. John and Adele's son Henri would be my gg grandfather. Henri married Mathilda(Domitille) Benoit). The marriages of Dauphinee and LeJeune, Dauphinee and Benoit and also Dauphinee and Gaodet(Gaudet) I believe, were intermarriages of French and Micmac ancestry.
Jean Frederick and Marie LeJeune would be the anecstors of those holding the Dauphinee, Duffenais, Duphenais, Dauphenais, Duphney, Duffney surnames and any other variation thereof, in Newfoundland.
There is a Duffney board at myfamily.com They might have the links you need. Did you try there? There are Fenix/Phenix Dauphinee descendants and you might be connected to them if not to me. Their ancestor adopted the surname while I'm still trying to determine if the name is original to my line or adopted.
I still say that Michael Dauphinee should be able to help but try posting to the board and you might have more success in finding more about David. I don't know if David had any children. I've met no one from his line yet.
Yes, Newfoundland is a great place to live. When I see pictures of where my ancestors came from, I can see why they chose to live here... the layout of the land is similar and was once richer in resources but it's still beautiful though tough to make a living.
Take care and good luck. Pleas keep in touch.
Rhon