Lost the passes for 9/11/2017...
I called the Help Desk at 407-939-4357 spoke to Jazz, as directed in the initial email I received yesterday. I was on the phone for 90 minutes. Jazz was great, super nice and helpful BUT she told me that the FPs for the party will eventually all be cancelled. As she put it, the computer system can now differentiate between a regular day ticket and a party ticket. Basically, before this year the computer saw all tickets as the same, but now, the computer recognizes a difference. Officially the party goers aren't supposed to be let in until 6 PM (if memory serves someone else posted this as well), although depending on park attendance that day they may be let in earlier, but it's at the discretion of the park.
At the end of all this I had to cancel my party fast passes, and rebook my fast passes on my last park day, 9/11/2017. I had a SDMT pass that day and they were kind enough to give me a special pass for that once cause I wasn't able to get it myself, and cause my family had one for the same time.
It was not a simple process, by any means, and took a long time. I would highly suggest cancelling your party FPs, if you want to avoid all of this. Good luck guys! May the force be with you.