Party admission is the same as Park admission, so you are good to go!
Historically is hard, as last year was the first year they were extended (In 2009 the League was already open late, they didn't cut back on hours until 2010).
Last year, if I recall, the decision was not made until mid-August. Mostly because they watched the reservations for
MNSSHP dates and discovered how incredibly booked they were. So they extended the hours only a couple weeks prior too.
The league does have shirt options. They change all the time which is why none are pictured in the first post.
One popular shirt right now has a bone look. The popular female option is a blue/green shirt with a mermaid (for the upcoming movie).
I did a quick google search and could not find either shirt in an image.
I recommend making a reservation at about 2:45, then participating in the 4:15 parade, then watching the 4:25 Pirate Tutorial.
Keep in mind, if you visit on a night with MNSSHP, then there will not be a parade.