I do wish you good luck and success with your application.

My verification of citizenship application, and my mom's, (through her father) are now in the processing phase.
We used this firm, also mentioned on DU. We have been very happy with them.
https://dfimmigration.ca
Many people are doing it without legal assistance, and there are multiple Reddit, Facebook etc groups offering assistance. I'm glad to have the legal assistance, especially as we will be sponsoring permanent residency applications for our spouses as the next step. We also submitted just before C-3 was passed, when my p2nd generation process was more complicated.

...on his mother's side were born in Ontario, except for his mother, who is listed as being born in Michigan. When I inquired about this from someone else distantly in the family tree, his guess was that, because my great grandfather's occupation was listed as "farmer," she was likely born while the family was traveling around during harvest season, working wherever they could find farms that needed help. Apparently, this was a common practice in the late 1890s.

One source lists her birth in Canada. She should have had dual citizenship, presumably.

Pretty much everyone else, for 2 generations, was born in Canada - both her siblings, both her parents, and her maternal grandparents.