While conducting unrelated research, I came upon a site that might help you. The Société historique et culturelle du Marigot (www.geocities.com/marigotlongueuil/) has birth and burial listings for 3 parishes in the Longueuil area. Look under the Saint-Antoine-de-Pades parish for the people you are searching. When you do consult the list, remember that a number 1 under the parent heading indicates that the deceased is a husband; a number 2 indicated a wife. You'll have a better idea of what this means when you consult the site.
I've checked and both persons you are searching for are in this list as well as 2 sons named Antoine.
They were most probably buried in the parish cemetery known as St-Antoine.