Don't panic, it's all still very much rumors and really the basis for the rumor is pretty slim, i.e. it's not inside information but just a TA saw a
Free Dining add on a TA site that was then quickly removed which could mean anything.
I for one would not be surprised if it's a couple days earlier than the 15th. Historically, Jersey week has been blacked out from Sunday to Saturday (which for this year would be 11/6/-11/12). Based on that you would think FD would start on 11/13. Another reason for thinking it would start on 13th is that having the check ins run so close to Thanksgiving (21st) as others have said does not make sense. Really the only reason for thinking they would wait until the 15th was because F&W ends on the 14th but if they were really trying to prevent overlapping FD with F&W then why would then entire last half of September be included in FD.
Worst case if it really is the 15th (or anything after 12th) then you can always do a split reservation getting the meal plan from 15-19 with all your tickets booked under that reservation and then do a separate reservation for 12-14 for only a room and I am almost certain you will be able to get a Room discount on that which of course is not as good as free dining but will help offset some of the additional food expenses.
Not trying to give you false hope but certainly there is no reason to lose hope.