Here is a list of the 15th century Hamerton wills in Yorkshire:
May 25, 1467. Hamerton, Hugh, Stokwith, May 2, 1467.
Feb. 27, 1405. Hammerton, Alan, York, merchant, Feb. 16, 1405.
Jan. 2, 1432.5. , Hamerton, Isabell, late wife of Alan H., of York, merchant, May
Sep. 28, 1466. , Hamerton , James, Weststokwith (bur. Misterton), Sep. 10, 1466.
Jun. 27, 1449. I , Hamerton, Laurence, esq., Adm.
Nov. 18, 1398. , Hamerton, Margarat, Prob. Act.
Jan. 9, 1480.5. , Hammerton, Richard (bur. Preston in Craven), kt., Oct, 4, 1480.
Feb. 28, 1464. 5. Hammerton, Richard, Rect. St. Mary Vet., York, Jan. 3, 1464
Most of them can be found in other records.
Alan Hamerton and his wife Isabel are found in Feet of Fines abstracts (link in earlier post)
and in Common Pleas cases. Isabel's will is here:
She and Alan had a son John. She had sisters Agnes and Ellen and a brother William.
I don't know how they connect with the family in Craven.
Lawrence and Sir Richard are in the 1563 Visitation and in several Common Pleas cases.
James Hamerton of West Stockwith could be another son of Lawrence, as shown in
Common Pleas in 1455:
York. William Clyveland, of York, draper, versus Robert Leventhorp, of Kyepas, Yorks, esq; and James Hamerton, esq, son of Lawrence Hamerton, once of Craven, esq, formerly of Pontefract, Yorks, esq, for a debt of 60 shillings.
I interpret this to mean that Lawrence Hamerton, defunct, had been from Craven while James was in Pontefract.
Richard Hamerton the priest was the plaintiff in Common Pleas for trespass in 1463 in York:
I haven't found Hugh, but since he's in Stockwith there must be a connection to James.