Disney won't allow you to stack discounts. If you book an AAA rate, then you aren't eligible for any promotions that may be available.
But back to your first question ....
You say you want to go in January, and that if a promotion comes out it will likely be announced in November. Making a reservation now will have NO EFFECT on your ability to secure that discount/promotion in November for January travel. NO EFFECT WHATSOEVER. I'll try to explain, but this might take a while. I'll use the word "code" to mean a discount/promotion.
When WDW offers a code, it does so because they want to increase the occupancy rate in their resorts. If a particular level of room in a particular resort has enough occupancy already, they won't even offer the code in those rooms. I'm going to make up some numbers here just for illustration. Let's say that in order for them to offer the code at Port Orleans French Quarter standard rooms, that the POFQ standard room occupancy rate (for your travel dates) must be below 80%. So let's say that for your travel dates that 81% of the POFQ standard rooms are already reserved. This means that the code won't be available for POFQ standard rooms for your travel dates. So, as you can see, it wouldn't matter if you already have a reservation or not.
But let's say that only 70% of the rooms are reserved ... that means Disney WILL offer the code for those rooms. If you already have a reservation, you will be permitted to apply the code (and get the discount or promotion). But if you DIDN'T have an existing reservation, you'd STILL be just as able to make a reservation in November and get the code.
I hope this helps you see that whether or not you have an existing reservation doesn't make a bit of difference about whether or not you can take advantage of a promotion. Of course, if you are going to travel during those dates anyway, then by all means make the reservation ASAP to make sure you don't get totally locked out of staying where you want to stay.