A long shot: There was an Aquilla Johnston, who died Feb. 5 , 1784 in Spotsylvania Co., VA had a minor son named John, thought to be born after 1770. Aquilla's widow was Elizabeth Winn (previously married to a Richards and a Fortson). Aquilla and Elizabeth also had older son named Aquilla and an adult daughter named Priscilla who had married George Goodloe and named one of her sons Robert.
There was a court case involving John and others suing the estate, and the widow had given land, etc. to sons by her previous marriage. I could not connect (so far) this group to my Johnston and Goodloe lines in Spotyslvania Co., so I did not pursue it further.