Hello! Im a Montreal local so heres my take on it -- Im not vegetarian but I know some pretty good spots
Libraires: Librairie Henri-Julien(my personal fav) -- Librairies Un livre a soi
Food: Lola Rosa, Nil Bleu(they have a vegan option), Our place(plenty of vegan option), Lov and Sham(i loveeee it)
Leisure: Bike throughout the Mount Royal(a lot of hills tho but when you get there, it feels like Amsterdam), thrift your way through the Mile-End, go to the Musee des Beaux Arts(a classic, last year they had a Basquiat exposition!), Bar hop on St Laurent
If you need more just tell me!