To add more information to the Fish discussion, but certainly not to solve anything... In Simeon L. Deyo's ''History of Barnstable County'', pp. 266-268:
He lists the "ten men of Saugus" who were given the right to settle at Shaume, now Sandwich, in 1637. He goes on to list the "three score" additional who were allowed to settle subsequently. In that second list are John, Jonathan and Nathaniel Fish.
He then lists 1643's 'able to bear arms', men aged 16-60, and in that list are again John, Jonathan and Nathaniel Fish.
Then he states: "The towns of the colony were required in 1654 to procure books for recording divisions and purchases of land, after which the records of Sandwich were more properly kept. The reader has been given the names of the original three-score families and the military roll which included the young men; now after the lapse of a few years, when the records, bounding each freeman's land have been arranged, we find the following named persons had land in addition to those alluded to: Jedediah Allen, William Allen, William Bassett, Nehamiah Bessie, Job Bourne, Michael Blackwell, John Bodfish, Samuel Briggs, Jacob Burge, Joseph Burge, Ambrose Fish, John Gibbs, William Gifford, Robert Harper, Edward Hoxie, Lodo. Hoxie, John Jenkins, James Skiff jr., Isaac Turner, and Thomas Tobey sr."
This seems to be the first mention of an Ambrose Fish, who either had not arrived by 1643, or was not yet age 16, but had and was by 1654.