Hello,
Hyacinthe Poupart is a breadmaker, born Aug 16, 1804 in La Paririe, son of Jean Baptiste Poupart & Susanne Dubuc. Hyacinthe Poupart married Josette/Marie Josephte Baret/Barrette Sep 2, 1833, in La Prairie. Having a bunch of kids in La Prairie and one of them is Joseph Hyacinthe born March 8, 1840 in La Prairie.
Now your Hyacinthe Inconnu is born June 19, 1840. I guess it is why as important man in his village, Hyacinthe Poupart is a godfather for a lot of children..
The couple Laliberté & Aquin are : François Collin Laliberté spouse of Louise Aquin, married at Ile Perrot, Feb 24, 1824. No children of their own so maybe it is why they adopt your Hyacinthe.
More ideas or data to come let me search & think about..... but I need an information to continue .... When , where and to whom your Hyacinthe married ......