I worked at my local
Disney Store for almost 2.5 years, until the store closed in January. I had no other job and was available to work almost any time. There were weeks when I had only "call-in" shifts - and I wasn't needed at all. Those got to be really irritating - especially if they were on a weekend, because you wouldn't know until 2 hours before your shift started whether or not they needed you. So - I probably averaged 10 hours a week, when factoring in the weeks I worked zero hours and around holiday times when I would work 20+ hours. If you want to work there because you need the income, look elsewhere - they can't guarantee you the hours, and the pay is minimum wage.
I wanted to work there because it was Disney, but now Disney doesn't own the stores. The 3 one-day park hoppers are the only theme-park perks left, and seasonal cast members don't get those. The people I worked with were great, and I miss them, but I DON'T miss working retail!!!
As for holidays - you're not supposed to take vacation time after November 1st. However, the past 2 years I still managed to go to WDW for 3-4 days in early December - just not over a weekend. And - I made my regular week-long trips during October.