hello Margaret,
For some reason I didn't get a notification of your post, (seems to happen often), and yes I can tell you that Alexander Smith and his 1st wife Agnes Muir with son Robert are buried in South Church - Churchyard in Whitburn and there is a headstone. He farmed Glenhutch Farm in West Calder then Tarareoch Farm in Armadale, where both he and his 2nd wife Marion Hamilton died. His descendants still farm in the West Calder district today, his father James "The Wishawtown Poet" was the Grandfather of John Black, "Breich Water Poet", many of the descendants still live and the Smith's still farm at West Calder.
I've attached a report on what I know so far about the Smith/Blacks and other connections, which you could have had many months ago, if I hadn't been browsing today, I don't know when I would have seen your post. Only hope that you get this one, and that the information is of some use.
cheers .... Meg