Ok I'll explain the confusion since it's out there now. We're keeping our immigration goals private just for identification purposes. I didn't want potential family members (who browse Reddit a lot) to catch wind given the details are very specific and it'll stir up some interesting discussions to say the least. The chances of them finding the post to begin with are slim, but as I mentioned, we wanted to keep it private. The details on this post are 100% accurate since I doubt anyone of them would be checking visajourney. I hope this clears the confusion. @manyfudge @Mike E.
Yes, https://ca.usembassy.gov/u-s-citizen-services/citizenship-claims/ -- Evidence of U.S. Citizenship of Parent(s). U.S. passport, Certificate of Citizenship or Naturalization, Consular Report of Birth Abroad, or a U.S. birth certificate bearing the impression seal of the vital records office that issued it and including the date of filing.
As manyfudge mentioned, I'll make a copy of her passport and explain to the officer that she is in today to renew her passport. If needed, I'll see if we can pull her in from her appointment to support mine.
Regarding joint sponsorship, if I understood correctly we can have my aunt (mom's sister who is living in the US) and my mom file that together.