RobDur on Family Tree Circles

Donald DURRAN & Janet SUTHERLAND were married 19 November 1801 in Olrig, Caithness. I have been trying to identify all descendants of that marriage and have currently found 992.

Although Donald and Janet only recorded the baptisms of three of their children, I believe they had at least 8 children. Of the eight, three lived in Caithness for the remainder of their lives and I am trying to find out where the other five disappeared to. None of them appear in the 1841 census and they may have emigrated to who knows where. Their names and estimated year of birth are as follows: -

Donald - 1802
Janet - 1808
Margaret - 1810
William - 1812
James Smith - 1817

I believe the William Dorren, a widower born Scotland, who appears in the 1870 census for United States in a home for males, aged 57, could possibly be the William above. Can anyone help?