I am also a descendant of David Ormiston, through his son William (then his son William, then his daughter Lydia Blair who married a Bruner). You mentioned a Jean Howison married to David Ormiston. I have also found her to be named Janet Hoag/Howerson.
In case you don't have the information, I have found David Ormiston (married to J Hoag/Howison) to be the son of James Ormiston and Jean Dickson. James was the son of John Ormiston and Agnes Wilson.