I don't know if this will help or not, but I took a quick look through the Dictionnaire Tanguay (if you do genealogy, I'm sure you know of this book). Anyway, I looked under "Montreauil" and it said to look under "Sedilot", so I did. In Book 1 (the overview book) I found a man named "Jean Sedilot dit Montreuil" son of Louis Sedilot and Marie Grimoult of France. Now, Jean is too old, but he may be the grandfather of the man you're looking for. Book 7 contains the generations that follow from him. While it doesn't list any marriage between a Durocher (or Desrochers, as is often the name at that time) and a Montreuil, I am 100% sure that one of these Sedilot dit Montreuil's is the person you're looking for. It will simply be a job of connecting the two. So it's may be a place to start. As for your information on Durocher (apart from also looking under Desrochers as I've already noted) you are correct, but I'd add Marie-Amable's full name which was "Marie-Amable St. Maurice dit Lafantaisie"