I was there in June. I didn't take my pin book into the park, wished I had. I saw a Sleeping Beauty marquee and the guy wanted WDI pins, which I have tons of, but I forgot them. He wasn't there the next day.
Lanyard trading was hit or miss. LOTS of scrappers everywhere. You can find the Cast Refresh series which is like our hidden mickey's, but their pins are larger and MUCH better quality. They are practically small rack pins of a single character. They also have trading boards in two of the stores at a certain time, and they sometimes do LE for LE so bring some cheaper LE pins. On these boards, they typically have a rack pin section too which also has Paris refresh pins, and seperately there is a hidden mickey section, very small. They may inspect your pins and if they don't think they are real they may say no.
At the PTN's, show up early. It seems everyone goes early and once the PTN pins are sold they kind of pack up and leave. I was dissappointed, next time I will go earlier. Trading was pretty easy. There are some really friendly and some turned up noses. Many don't speak English but pointing to pins or lining up pin for pin or pin for pinS is pretty universal.
ALWAYS run through the hotels too. Their stores often have LE pins for sale that the park sold out of. I found a Merida Mother's Day pin at the Yacht Club on 6/27/13 after it was sold out in the park a few days after it came out in May. It was in a case and I had to wait for a manager with a key, but it was worth the wait.