The Toronto or Air Canada forums would be a better place to ask these questions. Lots of knowledgeable people there.
The AC forum has a thread specifically devoted to the gifting of AC lounge passes.
The Sheraton Gateway at T3 will sell you a pass to their health club.
If you end up springing for a room, I'll chip in $50 towards the cost of a Starwood hotel if you let me have the stay credit.