Ol;ive Magdalene Allee was a a daughter of Abraham Allee who lived at Manakintow, Va in 1711-15. (internet postinmg, not proved by this writer) He and William Allee later appeared on a list of property holders in Henrico County, Va.
William Allee was on Manakin Creek in 1737.
Olive Magdalene Allee married Stephen Mallett. Her daughter Agatha married Stephen Spurlock all of the Hrnrico area. They moved to Mechlenburg County, Va where Stephen Spurlock died in 1774. He was born ca 1734so if Agatha was of a like age, her mother Olive was likely born ca 1710, give or take a few years. She was still alive in 1774 and witnessed Stephen Spurlock's will in Mechlenburg County.
So the dates make sense for William and Olive to be siblings, children of Abraham. Nicholasborn 1735 could have been a son of William and grandson of Abraham. Of course, Abraham may have had other sons who could have sired Nicholas. Anyhow, Manakintown and later Henrico seem to be the places to search.