OK! I tried to reply but not sure where it went - I've been trying to help someone in British Columbia [I'm in NS] who is a descendant of daughter Jessie and who is looking to find a United Empire Loyalist ancestor, so I've been trying to link Duncan to the UELs of the 84th who settled up the East River of Pictou. The records of that area are pretty non-existent as you have likely discovered.
Here is what I have for their children:
Jessie, born c. 1824, married Hugh Fraser
Mary B., born c. 1825, married John Lank
William, born c. 1828, died 18 January 1845 age 16 - son of Duncan and Jennie Cameron - from his gravestone in Riverton
Daniel - no dates except that his father gave him and a brother Archibald land in 1844
and Daniel signed over his land to his mother Jane in 1870 when he was living in Broadford Australia, near Melbourne
I've found no info at all on Archibald - still have to have another go at the probate records.
Jennie died 27 Nov 1884, according to her fairly modern gravestone.
Tried to attach a photo, but maybe I should take the tutorial!
Deb