I don't know that booking through AAA gets you anything that isn't available booking directly with Disney. I have a AAA membership and almost always get the AAA discount ... there is some limited availability, so I do call as soon as the rates are released and have it applied to my reservation.
Again, you have to choose 1 discount code to use. If others are announced, you just have to do the math and see which one works best for your situation.
As far as I know, PIN codes come randomly to random people. So far, no one has figured out how to make one show up in your mail.