Wow you have yourself quite a problem. Bridget is probably
one of the most used names in Ireland as is Mary. The Doyle name is in the top 5 of surnames. Douglas less known.
You are on the Westmeath board so does that mean you think they were from Westmeath! As that would help.
When did they arrive in Canada? This would be to determine if there is any possibility of finding them in Ireland.
The name Douglas will be easier. Did they marry in Ireland or Canada! I think what you have given as a marriage year/ record for of 1834 would be impossible as Bridget would not have yet been born, I think you mean his birth year!!
There is a search birth and marriage Irish History Foundation that might have birth records as early as 1834 & 1838. I would just go with James Douglas first, all you need in the Foundation is the name and a birth year. This will give you his parents names and mother's maiden name, parish/place. You can then start from there.
Having both names you can look for a marriage record on the History Foundation, they would of married at an average age of 20 for women 25 for men. They would of married about 1854 at the earliest, whether Canada or Ireland.
I do have marriages in Ireland for the Church of Ireland/Protestant from 1845-1862. No RC marriages. RC marriages in Ireland are located (if they exist) at the
National Library in Ireland. There would be millions of records so a Parish or at least a county to start. A county would have thousands or records it needed to go through.
The Latter Day Saints (microfilm) and Ancestry.com have records of RC baptism records.
I checked the CofI records for Ireland for marriages for
James Douglas the earliest is 1847-1861 and none married a Bridget Doyle. I would look in Canada for a marriage record but that is very early for Canada. There is a 1851 Census
that might have James Douglas listed, this would be called Upper Canada at this time. You should be able to google
the 1851 Census. Try either www.collectionscanada.ca
a good website for information is www.cyndistlist.com
You can look for passenger records on www.theshipslist.com
Passengers from Ireland would arrive in Quebec, travel to Montreal by steamship and then again by steamship to Stratford. These are pretty good records although many are
still being transcribed. It is pretty much impossible to find passenger lists from Ireland to North America. Many who were going to the US would come to Quebec as the cost was much cheaper then crossed to New York State.
The earliest existing official record now used as a census substitute are the tithe applotments. Dated 1820-30's James Douglas's father would be occupying land. These records are kept at the National Archives in Dublin or on Ancestry.com in its Irish collection.
The next official record that is used as a census substitute
are the Griffith Valuations, these took place between 1847-1874. Different years for different counties.
The Griffith Valuation took place in Westmeath in 1854. There is no surname Douglas there. There are 95 Doyle's.
Marriages generally took place in Ireland in the bride's parish but how would people from two different counties meet?
There are 623 Douglas surnames in Ireland during the time of Griffith Valuation in practically all Counties. There were 88 James Douglas, any of whom could be your James's father or grandfather!
I hope I haven't put you off searching. Go with the History Foundation for a birth record for James Douglas, then get back to me by replying to this posting.