Reviewing the Kempton/Kimpton Families book (colonial US Kemptons and Kimptons) there is no listed Covel marriage.There are the 2 Henry Kemptons (1 carpenter from Hartford, Conn to NY and Major Henry) of Fairfield, Herkimer, NY.
There is a Henry appearing in the 1830, 1820, and possibly the 1810 (at Henry Knapt of Warren, Kerkimer, NY).
There (I believe) is conflation of some children listed to Major Henry that should be Carpenter Henry.
Further review of the Ke/Ki Families shows me that there are 2 apparent Henrys hanging as dead ends.More research if these are the needed Henry.
But a death cert of Thomas in MN would be invaluable, or that of his marriage cert showing all the parents names, birth places etc.