If you know for sure that Nicolas remarried to a Marie Hudon, the info provided by Muriel makes sense.
Ham-Nord is located in the Eastern Townships, not far from Thedford-Mines.THis may have been theplace of origin of Rosanna and where she was buried.
Let me search for the record of the second marriage of Nicolas.It should state that he was the widower of Rosanna Caraey.The place of marriage, incl. the parish, may be an indication of where they lived in Montreal although the marriage normally occurred in the bride's parish.
If that fail, I will have a look at the Lowell Directory for Montréal.I am not sure as to whether or not it is avail. on line; you may try.The street name would help in determining the parish where Leon Clementine was bapt.