Anne,
In case you don’t have the information, here’s Joseph & Agnes in 1901:
http://www.census.nationalarchives.ie/pages/1901/Armagh/Camlough/Thomas_Street/1036225/
I’d guess it was a mixed marriage as they married in the Register Office. At the time of the 1911 census they had had 7 children, of whom 6 were still alive. I think this is Joseph marrying Nancy Sands in August 1872 (Nancy & Agnes are interchangeable in Ireland and Scotland):
https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1872/11314/8151643.pdf
The GRONI website lists the following children to those parents:
Nancy 3.7.1872 (indexed under Weir on GRONI and Wier in irishgenealogy). The couple said they were married though it seems they were not.
Elizabeth 16.3.1874
James 10.9.1878
Samuel 19.7.1886
There were evidently also Annie, Esther & Joseph but I have not been able to find their births. Search under Wier as well as Weir and you may find them. I can see Annie Weir listed on plot 10 in Thomas St Bessbrook from 1914 onwards in the Valuation Revision records for Camlough. That was a house and small garden (probably provided by the mill). I don’t know where the Cottage was. It doesn’t appear to be listed though you could search the Valuation revision records for Camlough to see if you can spot it.
https://apps.proni.gov.uk/Val12B/Search.aspx