Sorry, I don't know anything about a volunteering program to earn free nights.

As for upgrades, yes, they are guaranteed. That is probably the best part of the FPC program. If the proper room categories are available at the time of booking, you have a confirmed upgrade. You need to have availability in both the Fairmont room category (which is the rate you are paying) and the category of the room or suite you will be upgrading into.

For your stay at the BSH, I would book that one fairly early. Not because the hotel will be full, but because the best upgradeable suites may be gone. At the BSH, you can book the Fairmont room and upgrade into either the Jr. Suite, the Stanley Thompson suite, or the main building 1-Bedroom Suites. Go for the 1-Bed suite in the main building. They're very spacious. Might be a little outdated, but then so are the other suites you'd be choosing from.

In fact, I would also book your CLL rooms now. The CAA rates are cancellable. Book now, and if the rates go up, you've locked in a good price. If the rates drop, or a nice promo comes along, you can change. It's not necessary, but basically you've nothing to lose by doing it.

At the BSH, the CAA rate is not always the best deal, but it is at least cancellable and a good one to start with, until the seasonal promotions are released. I think it's only about 20% off at that property with the CAA rates, so instead my last booking there (for a stay at the end of this summer) was on the moments offer to pay for 2 nights get the third free (which has since been amended to pay for 3 and get the 4th free). I booked that one, used a suite upgrade cert, and a free night cert. Basically getting 4 nights in a suite for the cost of 2 nights in a basic room.