I figured I'd start a topic here to help future Montreal cheese makers find some of the ingredients needed to make cheese.
Unfortunately, I don't think there are any stores that specialize in selling cheese making supplies in Montreal. I toured the city for a good two weeks before I could find someone who knew what rennet was!
Anyway, I was able to find some ingredients at La Baia dei Fromaggi
. Last time I checked they had rennet (15$ for a small bottle), Abiasa Mesophilic II, Meso Aromatic Type B, & Thermophilic B. That should be enough to get you started. Also, they have an awesome collection of cheeses (more than 300 according to their website).
For Calcium Chloride you can go to a home-brew store. There's one on St. Dominique, just one block east of St Laurent called La Chope à Barrock
& and one further out in Baie D'Urfe called La Cachette du Bootlegger
Hope this is helpful! Also, if anyone knows of any other good places for supplies around Montreal, please let us know!