i think kids at that age can go through a lot of odd phases that last for a week or so and then resolve. I know we had issues with my daughter struggling with sleeping around 15 months and I was at the end of my rope. 1. Because Iwasn't getting any sleep and my DD was cranky bc she wasn't getting enough sleep. Anyway, I ended up reading the Ferber book (which has a lot more info on kids and sleep than just the 'cry it out' thing). Anyway, he suggested that as kids get older pacifiers make it easier to fall asleep but causes them to sleep lighter and awaken frequently. We had tried everything except for eliminating the binkie - took it away and within 2 days sleep was perfect!
I am not suggesting that the binkie is your problem but I would totally recommend looking at his book to see what might be going on with sleep. It's such a great resource.
On a related note, I imagine your child will act very differently in WDW. We have gone many times and I can tell you sleep patterns change - later nights, no bedtime routines, and late mornings. Also, I find that the cast members are wonderful about engaging with your kid so they might be a little less clingy. Good luck!