To extend TRV from Canada, you need to go to
<http://www.cic.gc.ca/english/e-services/extend-visit.asp> File it online, attach all the necessary document, I attached documents listed at <http://www.cic.gc.ca/english/e-services/extend-visit-doc.asp>, For Financial stuff I attached my pay-stubs and Employment letter. After few weeks or a month or two, they sent us the Visa extension + Request to perform Re-medical before the expiry of present TRV.
After PPR Request, I sent my wife's passport via FedEx (CanadaPost) to my inlaws in Pakistan. They forwarded to CHC,Isb. Later CHC,Isb sent it back to my inlaws, and then my in-laws forwarded it to us via someone who was flying here.
You will need to fill the last section of PPR Letter that you authorize your someone in Pakistan to pick up your passport, you place their address and phone number.
I heard that it's illegal to transfer passports via someone hand, but FedEx and other postal services didn't complain to me. I guess you can sign an authorization letter (incase of postal services ask) that XYZ can forward your passport.
For Medical Results, by CIC-Law&Rules DMP-in-Canada will always forward it to CIC, Ottawa. Since the PPR Request letter says that DMP should forward it to New-Delhi. CIC-Ottawa will forward it automatically to CIC-New-Delhi, we don't need to do anything. I just called <1-888-242‑2100> to confirm if they will do it themselves and how much time they take, they replied Yes and Approx 2-3 months.
In our case, My inlaws received Re-medical and PPR letter together, They forwarded the Package to us, then I first had my wife Remedical done in Canada. Then I started pinging CHC,Isb every 4 weeks to confirm if they received the Re-medical exam. Mid-Jan I received their reply, then I sent my wife's PPR-letter+Passport to my inlaws via FedEx.
P.S Ping me again if you need further info. I'll post this on the thread too.