Couple notes on the discounts: I took out both my AAA card and my AP at every register yesterday, and was told in all cases that I could use either, they were the same discount amount. Although at the picture counter at FJ, they couldnt find the code for the AP, so they used my AAA. As a matter of fact, they opted for my AAA card first at most of the counters, Dervish and Banges being the exception. Interestingly enough though, at the picture counter, I had to fill out a receipt with my name, address, phone, etc along with the discount - receipt stated something like "you have received a discount, to process we need the following information". All the other counters just swiped my card and discount was given - no extra paperwork. Dont know why the picture station was different.
But, given my experience, some good news for AP holders who dont also have AAA.
Also remember, some of the merch is available in the main gift shop at the enterance, as well as the main shop in the other park and the UO shop in Citiwalk as of yesterday, and your AP discount definately works on the HP merch there if not in WWoHP.