Yes, there were two men with similar names: 1. John Fost of Dover, he married Mary Chadbourne and then Sarah Goff, widow of James Goff.He was from England. He died in 1699 and left a will.
2. John Foss of Rye, he married Mary Berry.He was also English, probably from Paignton, England.His uncle John Jackson was also in New Hampshire. He deeded his land to his sons in 1710 but did not leave a will.
Guy S. Rix write a Foss genealogy in the early 1900's and erroneously listed the ancestors of John Foss and a family from Denmark. you can read my blog on John Foss & John Fost at jeaniesgenealogy.com I have a few more details on my blog.
The Foss family is a real tangle and it is hard to decide who belongs to whom.