Hi Sherry
Yes, all Gideon's siblings were also baptised in Yetholm. Their father John and mother Isabel were also married in the same place in 1791 and - wait for it - at a double wedding with John's father, who got married for the second time. I know these details are accurate. I got them from Scotland's People.
As far as I know Isabel also came from Roxburghshire. I think her father was Adam Wood. I haven't been able to be absolutely certain about him.
George and Thomas were Gideon's other children. George became a teacher in the church school and went to Canada. Will tell you more about him when I get on the laptop - iPad is not so good for many screens!
Thomas was a shepherd like Gideon and went with him to Argyllshire and became a manager, like Gideon. He stayed in Scotland.
In 1841 Margaret was in Roxburghshire with her mother. Will send you details later.
Was very interested in Andrew McGregor. I saw from one of the US censuses that he says he is England. I think I just might have found him.
More later.