Hi Danvers.
1. Congratulations.
If they do the HM makeover to Nightmare Before Christmas (we don't know due to the 50th anniversary that they will still be celebrating... yeaaaaa), yes, it will be up -- it's usually up the first week of October through the Christmas holiday.
2. Yes, IASW will be up - they usually begin the holiday version first weekend in November.
3.
Disneyland begins its Christmas holiday season by the first weekend in November. You'll have the two attractions mentioned, most decorations (& they'll all be up at Thanksgiving), Dickens carolers, huge Christmas Tree on Town Square, cookie decorating, Christmas flavored candy/treats throughout the park, and Christmas decorated desserts - Nightmare Before Christmas style at French Market/New Orleans Square, Holiday fireworks, and snow. The parade won't start until Thanksgiving Day, and I forget whether Santa makes his appearance before Thanksgiving or not.
4) Before Thanksgiving weekend, you can get pretty good rates at the hotels. This still typically falls within their value season, and they may have 3rd night/4th night free promotions, and sometimes Disney will have a 4th night free/free character breakfast (or some type of promotion like that), if you book at one of their hotels.
I'll give you an example.... the Sheraton is a really nice deluxe hotel near the Disneyland Resort. At the time when no one had specials, they were offering the 3rd night free.
Pros for the Sheraton
Beautiful grounds
Very nice interior
Pretty decent pool
Largest rooms in the area
Really comfortable beds (those heavenly beds)
Have their own shuttle to take you to the DLR
and, I like it the best after a Disney Resort Hotel
Cons for the Sheraton
Not a Disneyland Resort Hotel
Parking fee of $10 per night
Not really walkable distance to just pop over to the Disneyland parks & Downtown Disney, so you have to rely on their shuttle