I have just come across your posting from 1998. Are you still interested in Margaret and James? I am a direct descendant of James and Mary (nee Flett) Linklater. They arrived in Sydney in 1857. Mary died in 1888 and James married Margaret Jennings in 1890.
The only information I have of Margaret I obtained from their marriage certificate and from James' death certificate (1901). I presume she must have re-married because James and Margaret did not have any children.
Please contact me if you have any more questions. My family tree is up in Ancestry.com