Hi Marcie,
Congratulations on booking your next trip - September is a great time of year to visit the Walt Disney World Resort.
Mickey's Not-So-Scary Halloween Party is my absolute favourite Special Event. Although the exact dates of when it will be held in 2016 have not been announced as of yet, I can tell you that last year, the dates were released at the end of February. I would imagine that the 2016 dates will be announced at around the same time this year.
The good news is that the very first party of 2015 was held on September 15, so based on that, I would say that there is definitely a good chance that you will be able to attend Mickey's Not-So-Scary Halloween Party during your visit.
I can totally understand you wanting the scoop on when any
Special Offers might be released for this Fall. Although Special Offers do change all of the time, last year, a Free Dining Offer was made available to the general public for booking on May 7 for arrival dates beginning at the end of August through late December, with blackout dates. Do bear in mind that availability will be limited and therefore if you do see a Free Dining promotion come available which covers the dates of your stay, be sure to take advantage of it immediately.
Wishing you a magical trip filled with memories which will last a lifetime!
Emma