You will receive a letter informing you that your file has been transferred to another office. That's the case with my application being transferred. If no message is received about this, your file probably remains at the Mississauga office.
I guess for a police certificate, as long as it can prove no criminal record til a recent date, expiration doesn't matter that much? I'm not sure about this. My parents' PPC doesn't have an expiration date.
Same boat; my parents' first medical will expire at the end of this month. We received a new medical request in May and passed it again in June.
You can check my timeline in the signature below for details.