This is ridiculous. The case from the 20s went nowhere because the Crown had ruled on the matter almost a hundred years earlier. You need documentation of your own to open a case like this. You obviously don't have that. What is the basis of your claim? From all appearances, you're pursuing this on the basis of a fairy tale. Even if you really did have the documents, I would suggest you consult a Canadian lawyer, where you would find that with the ruling in place not once but twice, you have no standing to bring a new action after all these years.
No one's going to tear down the Place d'Armes and hand the land over to you, particularly given the fact that you would need to get the permission of the majority of descendents of Marie Archambault Tessier in order to even represent their interests. How exactly do you plan to do that when you're talking about a good chunk of the French Canadians in both Canada and the U.S.? Moreover, for all of your efforts, it wouldn't take much for the Banc du Montreal to seek out their own contacts with descendents and file an action opposing yours. Use your head!