Some of the birth dates were drawn from sources other than the article. Confusing dates as I think it was John that was born 1786 not William. I have William on census records and cemetery records he was born 1811 not the 1786 which is why I think the 1786 birth date belongs to John. Have read the article many times and it is still not real clear to me but have the other sources posted below.

1850 New York, Ulster, Woodstock, image 37 taken Sep 21
Duvall, William, 38, m, farmer, $1500, NY
Hannah, 36, f, NY
Francis, 14, m, NY
Martin, 13, m, NY
Albert, 8, m, NY
Elizabeth, 5, f, NY
William, 2, m, NY

1860 New York, Ulster Co., Woodstock, image 34 taken June 22
Devall, William, 49, m, farmer, $3000/378, NY
Lucy C., 38, f, NY
Francis, 24, m, day laborer, NY
Martin, 22, m, day laborer, NY
Albert, 17,m, farm laborer, NY
Elisabeth A., 15, f, NY
William J., 11, m, NY
Benjamin, 9, m, NY
Edwin, 7, m, NY
Chauncy, 4, m, NY
Mongomery, 1, m, NY

BURIAL: Hudler Cemeter, Mount Trempter, Ulster Co., New York for William DeVall
b. 1811 d. Jun 15, 1860 sp Hannah DeVall (1814-1851) 48yrs 6 months 20 days