Well, lucky us, all of the Quebec records were just indexed and digitized and in less than 24 hours, the Gardner family has emerged. The Gardners were a well-established Montreal manufacturing family. Robert Gardner, Catherine's father, owned "Robert Gardner & Son", a foundry which specialized in making biscuit-making equipment. Robert and his wife Helen McGregor were emigrants from Paisley, Scotland. They arrived in Canada in 1842 aboard the brig Favourite. Robert was a trained pattern-maker and worked in foundries in Montreal and New York before starting his own business in 1851. Robert and Helen had nine children (at least these are the ones I could find!):
Daniel Campbell (1846-1852)
William Smith (1849-)
Catherine Jane (1854-1914)
John David (1855-1857)
Helen Janet (1857-1923)
Mary Ann (1859-1923)
Harriet Abigail (1865-1929)
I found a nice biography of Robert Sr, which you can look at here.
Robert Jr. took over the business when his father died in 1890. (Robert Jr. was quite distinguished in his own right. He was a colonel of the Sixth Fusiliers and took part in the Fenian Raids of 1866 and 1870. See his biography here.)
You may also be interested in Edgar Samuel Hird's baptismal record and Edgar Maxwell Hird's baptismal record in which he is mistakenly called a daughter. I have also created an album with records for Samuel Hird & fam and EM Hird and fam.
Here is a slideshow of the Gardner family documents and photos to date: