Hi Little Bernie,
Unfortunately, it seems that you do
not have enough information. And even if you had more information, you might well not be able to find them in Scotland before they left. This is for two reasons.
One is that statutory registration did not begin in Scotland until 1855; before that the only records of the three sons would be church records of their baptisms - and many children were not baptized and/or the registers of the particular church may not have survived or may not have been indexed.
The second reason is that they were Roman Catholic. Virtually all of the records in the IGI and on the ScotlandsPeople site are from parish registers of the established (presbyterian) Church of Scotland.
A search in the Family History catalogue on the FamilySearch site shows that the LDS have, for each of North Uist and South Uist, filmed only registers of the parish church (i.e. established Church of Scotland).
The National Archives has extensive Roman Catholic records but they are not searchable online.
Click here for the National Archives of Scotland CatalogueClick on 'Search'
In the RefNo box, enter RH21
There are 11 pages of records of 'Roman Catholic Baptismal and Marriage etc Registers, 1703-1976' including several records for South Uist.
If you return to 'Search' and enter CH17 in the RefNo Box it brings up 'Roman Catholic Church in Scotland'. Click on Details and it states "The Scottish Catholic Archives, Columba House, 16 Drummond Place, Edinburgh EH3 6PL, holds the major collection of Scottish Catholic records of historical interest, although in no way supplanting the archives of local dioceses and other bodies."
http://www.dioceseofargyllandtheisles.org/content/may be of interest and has a link to the following site on the Catholic Church in the Western Isles:
http://www.pa44.dial.pipex.com/If family folklore is that they came from North Uist, it shouldn't be dismissed - there could well have been
some Catholics there.
I don't know how reliable the following site is
http://www.rootshebrides.com/index.phpbut, under Research Tips & Resources, it states "It can be very useful to know where the emigrant settled first after leaving the Hebrides. There are definite patterns in emigration, so in Cape Breton, for example, settlement in Mira or Gabarus suggests a North Uist origin, while settlement in Iona or Christmas Island makes a Barra origin almost certain. "
I see from the following site
http://www.theshipslist.com/Research/canadarecords.htmthat passenger lists of arrivals in Canada were made but that, unfortunately, those pre-1865 were not archived!
Are there any early land records, early censuses, histories of the region where they settled which might help pin down more information? Do Canadian death certificates contain information about parents? Any gravestone inscriptions?
Good luck,
JAP