I don't think it's related to PPR at all. I just got RPRF, PCC, and medical request. They didn't ask to submit Supplementary travel info form though. I thought everyone was being asked to ?I got PPR request after almost 1 month i got pre arrival letter.But to be honest I dont think that is not that much related with getting PPR email.Thats my personal opinion though.
Also, on GCKey, I only see options to upload PCC, and RPRF receipt. Nothing about medical. I guess I don't need to upload any confirmation after medical is done ? Doc will send the results directly to IRCC.
My file is being processed in Ottawa, but parents are in home country. I'm going to assume they can still do the medical in home country.