Oops, I left off on mid sentence. That was John Fernald who married Hannah Gerrish on 10 Nov 1791. He was the son of Joshua Fernald and Elizabeth White.
Joshua was the son of John Fernald and Margaret Fernald. This John was born 25 Aug 1718 and reportedly died in 1790. The son of Hercules Fernald and Sarah Hincks. He married Margaret on 7 Sep 1739. She is the daughter of Nathaniel Fernald and Margaret Tripe. John and Margaret Fernald also had a son named John born 20 FEB 1750. who married Mary Fernald on 25 Nov 1772.
So John and Margaret would also make a good canidate to research as the possible parents for Miriam, seeing that he died about 1790. And they supposedly had a daughter Miriam born 20 APR 1762. Unless she was a twin or these children were confused, they also had a daughter Maria born on that same date who died Nov 1812 according to internet sources.
Seeing that there weren't that many Johns in Kittery who were heads of their households in 1790. You would think that one of these could be your John. Either that or the data I have seen thus far is corrupted or rather was easily confused because there were so many Johns!!