Great to hear from someone at long last. I have always assumed that Marjory & Marsellas Dick are one and the same. (Marsali is the Gaelic for Marjory). The children I have for her and John are : John 16 Feb 1802, James 31 May 1804, Agnes 11 Jun 1806, William 16 April 1808, Hugh 8 Feb 1810, Barbara 3 Mar 1812, Samuel 28 Dec 1813, John 5 Sep 1815, Margaret 28 Dec 1816 - 15 Mar 1895, James 30 Oct 1818 - 25 Mar 1891 (from whom I'm descended), Robert 22 Jun 1821 and finally John 3 Oct 1824. I've got pretty full records for Margaret & my James. Given that Marjory & John were so good at having the children 'registered' I am surprised that I have never been able to find their marriage. I don't know how familiar you are with the Scottish naming patterns - it isn't unusual for a name to be used over (and over) if babies didn't survive.
I would love to swap any info with you..
I live in Dunfermline by the way. Please feel free to contact me on my email address.