Benjamin Richards, s/o Thomas and Weathean Richard, b. "say" 1638, m. Boston 10 Oct 1661 Hannah Hudson.
The text of the cited source S1 provides further material to analyze. In his father's will of 17 Dec 1650, Benjamin is listed last among the sons, suggesting he is youngest. Since Joseph's birth is estimated to be 1636 (or after), Benjamin's birth is therefore estimated to be 1638. His wife was born 1643/44 and his marriage in 1661, which all seems consistent with a birth about 1638. He is explicitly mentioned as under 21 in his father's will, so with certainty we can say born aft. 1629.