At this moment work permit extension is taking nearly 100 days both online and paper application. As you have work permit till October 15. I suggest you to wait till last week of September. If you still haven't received the PPR, then file for work permit extension. So when you file your work permit you will fall under implied status and your work permit is valid until you get the result of your work permit application. This buys you another 3 months of time. Hopefully you will receive the PPR by then. In case your PPR is delayed, still your work permit will be approved and you can stay legally in Canada. If not you will have to restore your status. If your PPR is delayed and work permit is rejected you will have 3 months to restore your status. So you got enough time.
ALL THE BEST!!!