Hello Cupcake,
I'm new to this site and just came across your posts. Robert J. Moffat is also my Great Grandfather. As a matter of fact, the photo of him in your post was posted by me on another site.
By the sounds of it, you must live in Scotland, unfortunately I live in Canada so access to record offices is not easy for me, however I do have a lot of old family photos and original birth records.
According to several sources, Robert J. died Feb 4 1926.
He and his first wife, Margaret Mein had 7 children (2 girls - 5 boys). After Margaret passed, Robert J married Annie McLaren on 18 Feb 1889 and together they had one child, a son, Robert Johnstone. Robert Jr. died 31 Jan 1899. Cause of death; Heart Disease -3 years, Bronchitis -8 days, Congestion of the lungs -6 days. Source: Death Record (Scotland’s People).
In 1910, Robert J's son, George, and his family at the time immigrated to Canada and finally settled in Vancouver, British Columbia. George and his wife, Jane MacKay had 5 children (4 girls - 1 boy).
I have great deal more information on the Moffat side of the family, but nothing on the Tait side, so your post is of great interest to me. Anything you would share would be greatly appreciated.
I have been very fortunate to connect virtually with 3 second cousins (2 in Scotland and one in Australia) all of which have provided me with a great deal of helpful information.
As I mentioned, I'm new to this site, so I hope you get this message.