Dear Peggy,
Thank you for the info on Hugh and Jane Strange and their emigration. Unfortunately I do not have the names of parents of either Mary Johnson/ Johnston or William Barklie Strange. By applying the Irish/Scot naming pattern, Mary's parents could be Robert Johnson/Johnston and Janet Todd. William Barklie Strange's could be Hugh Stuart Strange and Christina Barklie. Plan to check the 1813 First Ballyeaston church census for this guess.
Please let me know if you find any fit. This is who I have for children of William Barklie Strange and Mary Johnson:
Hugh Stuart Strange, b. July 21, 1824--you have info
Janet Todd Strange (called Jenney) b. April 24, 1826
Christiana Strange b. Feb. 28, 1828 married Robert Redpath
Sarah Elizabeth Strange b. Feb. 28, 1828 (died young)
Mary Anne Strange b. Jan. 16, 1830 married Samuel Elliott
Robert Strange b. June 5, 1832 (I think he likely died between 1841 and 1858)
Elizabeth Strange b. August 8, 1834 married Robert Leathem
Agnes (Nancy) Strange b. Sept. 5, 1836 married James Hart
Sarah Jean Strange b. Jan. 16, 1839 Married John Crowe in Belfast
If you need more, please let me know.