From Boston records (https://www.familysearch.org/ark:/61903/3:1:S3HT-XKGQ-9CT?i=60&cc=2... and forward), we have that Hephzibah was born on Feb. 16, 1675. (The year should be 1676 based on the marriage of Gershon and Sarah.) Also, Dorothy was born Dec. 7, 1677, in Boston.
From Groton VR (https://archive.org/details/vitalrecordsofgrgrot/page/112/mode/2up), we have that "Jo[blot], d. Gershon and Sarah" was born Dec. 30, 1696.
I am still looking for solid references for the births of the other children.
Dean Richard Hobart - Is this your direct family? I don't want to mess up anything, just get it correct.