To answer your question about getting the merchandise, yes, you can. There's a number on any receipt you may have from any Disney gift shop....call it. You can then ask for the main merchandise number. Alternately, you can look up the number in one of the WDW guidebooks, such as The Unofficial Guide....etc. I saw it in one of the books, but not sure which one. You can also just call the main number and ask them for it.
There is no listing of items available for purchase from WDW. You have to "know" what you are looking for, generally at least. I was looking for a princess pillow I saw while down there over Thanksgiving. I called up and described the pillow and she was able to find it on her computer. I ordered it with many other items; mints, mickey ears for my car, mickey roni and cheese, and the Epcot Candlelight Processional CD. I paid $20 to have it shipped by Christmas Eve. Well, the whole package came but no pillow! It said that they were out of stock. Ugh. Buy it when you see it is my new motto! The Epcot CD I mentioned it wonderful by the way.....so is the show. Just beautiful! Good Luck.