Hi Alex and welcome to Rootschat,
It's been a while since you made your posting so perhaps I can help a little. Firstly, I am not related to the McGhie family but I have done a certain amount of research on the families of James McGhie and Jane Close through connections they have with other families I research in the Cambusnethan area.
I have Andrew McGhie (son of James McGhie & Jane Close) married to Janet LOVE. She was buried 02 Aug 1907 aged 46 with at Cambusnethan cemetery Sect E Lair 1286 but I don't know if there would be a headstone. It is the same grave that Andrew was buried in 1909. By 1903 there are at least 4 children born to this couple but there was only one child, Jeanie aged 11 on the 1901 census. I take it that the James McCreaddie McGhie you refer to was born to this couple though you mention his mother being a Jane McFarlane so perhaps you could explain a little how that all works and when James was born.
I have located an Agnes FALCONER, a wife, resident Wishaw, aged 34 yrs, married, father Wm McFarlane, mother Jane Kay, buried Old Graveyard, Cambusnethan 4 Apr 1874. It looks like she was married to a Wm Falconer.
I hope this gives you something to work with.
Regards, Sage.