It's just a storage system for the vapor. The ECU controls the purge solenoid and opens it so the vapor can be drawn into the engine. That's why you don't want to overfill your tank. You can get liquid gas into the canister assy and mess things up.
I found rust on the inside edge of both rear doors. Where the door skins are bent over the door frame there is rust bubbling the paint. Here's a couple of pics.
Just went an did a little experiment with a rubber mallet. I dropped the seat backs and tapped around the latch with the trunk lid closed. Nothing happened. The escape handle hangs down and it doesn't take much pull to pop the lid. My bag must be snagging that handle.
Here's something. I keep my 3 ball bowling bag in the trunk. Sometimes it shifts and pops the trunk open. It doesn't take much to make it happen either. I'll be tooling along and the "Trunk Open" light will come on. Never had that problem on any other car.
The rear drive shaft is in 2 sections. The carrier bearings support the sections. I only had 10,000 miles on mine when it went. It started as a low whine, almost like tire noise and got progressively worse.