After searching 1790’s census at Southwick and 1790’s census at Hamden, I didn’t find any people who is related to our main character – Exeter. At first I guess is because that most of slaves’ surname are given by their mother, because they have no idea who their father is. Also some freed slaves were known to have changed their surnames after gaining freedom. And when we consider that Exeter is not a slave but only a free African American, the potential of finding information about him on record is challenging.
On the other hand, searching Hanchett in Suffield comes out result of Capt. Oliver Hanchett who born in 17, August, 1741 and died in 20, September, 1816, who married with Rachel Gillet and had nine kids, one of them had the same name to his father, Oliver Hanchett, who dead in the year he born. However, keep searching the latest posterity of Oliver Hanchett, I found Theodore Hallas Hanchett, which lived from 1920 to 2007. Thus, unfortunately, we cannot get more information by talking to Oliver Hanchett’s offspring face to face.