1. There are usually costume events held Oct 31 in DTD and Pleasure Island.
2. MNSSHP is a limited admission ticket: In the past Disney has sold approx 10,000 to 15,000 on a given night. But these events are becoming more popular, so it is possible that Disney may be selling more tickets to each event.
Also, people not attending the MSNNHP who are still in the park after 6pm are not forcibly ejected from the park. Some of these people remain in the park, just strolling along watching the events and all the costumed people. They cannot ride the rides, nor trick or treat.