I am also a descendent of John Collison and like you have reached a brick wall trying to locate his parents and other ancestors.
I was recently at a family funeral, Honery Collison Pye and the same week Susan Campbell Elliott (mother was a Collison)
both are first cousins from the Parry Sound Area.
They are the Grandchildren of John Albert Collison, son of Silas and Lydia.
I will kepp hunting!!