Hello Helen21,
Thank you for weighing in. Congratulations on making strides to identify your Ann Henderson (m John Fraser).

I, too, have made significant progress since I started this post years ago.

My 2x great grandmother, Ann Henderson m Robert Bain. Her marriage record says her mother was Innes Berry who married John Prosser. Ann's father was "reputed" to be a be a "Henderson, farmer". I confirmed both the Berry and Henderson relationships by geographic proximity and DNA.
Innes Berry lived close to the farm of Alexander Henderson Jr 1831-1915. He was noted as father in the birth record of an illegitimate child, William Henderson 1849-1919. I match with descendants of that relationship.
Alexander Henderson abandoned William's mother and sired my 2x great grandmother with Innes Berry. He then married, though had no children with his legal wife.
Ann's mother, Innes, also had a son with her husband, John Prosser. I have confirmed DNA relationship with descendants of that man as well.
Happy sleuthing.