In the earlier posts have read people doing that. In fact I felt that helped them speed up the process. Just sort out how you can get PCC from Canada. Again have read many people get that as well from here. Just check for all the PCCs you need.
Also go over the link below. It seems earlier medical exams are eligible for now (says policy is in effect till Oct 6, 2024) given certain conditions are met e.g. the applicant is in Canada, medical is less than 5yr old, etc.
https://www.canada.ca/en/immigration-refugees-citizenship/services/application/medical-police/medical-exams/requirements-permanent-residents.html
Once they are here I understand you will need to submit webform to update their address and also let IRCC know of IME number for super visa if it meets conditions mentioned on the link above.
Just my 2 cents based on following this forum. I am not an immigration consultant. You can also post this question on 2021 PGP thread and/or call IRCC and ask this question from them.