I can add a bit to the "Amherst connection" that you mentioned:
You mentioned the marriage of Abigail Amelia Cove to George Miner in Amherst. Abigail's brother (William Cove) married Elizabeth Miner in Amherst. The marriage bond was taken out on Feb. 11, 1844 and the marriage occurred on Mar. 10, 1844.
Do you recall where you learned about the marriage of Henry Robinson to Eliza Harriet Cove?
BTW: Harriet was, indeed, born in 1815 as you thought. Here birth is registered in the Township Book for Horton, Kings Cty.:
Thomas Cove and Phebe Reid married 20 Dec. 1810 and have issue:
Mary born 21 Dec. 1811
Abigail born 9 Feb. 1813
Harriet born 7 May 1815
William born 5 April 1817
Richard born 18 April 1819
Ann born 2 April 1821
Gerry