We are considering a trip for Thanksgiving week 2015. I know that Haunted Mansion and It's a Small World close down for holiday overlays each year. Are they typically reopened by Thanksgiving week?
I don't know if you subscribe to and/or follow the
Disneyland at Christmas/Holiday Season Superthread, but I have a Dates to Remember post on the first page --
HERE -- and I keep track of when everything officially starts, soft launches/opens, begins to appear, etc. (and some end dates too). The post I just linked has the info for the last 2 holiday seasons, and I will be updating it/revising it for this year -- so stay tuned.
As dina444444 said, both HMH and IASWH (and likely Jingle Cruise too) will be open for Thanksgiving week, as will most of the holiday season activities/décor/entertainment.
Haunted Mansion Holiday will likely start when Halloween Time starts (which could be anywhere from 9/10 to 9/15 this year). It is actually staying open several days longer than usual during this current holiday season, so I wonder if could open a few days later than usual in September (we'll find out eventually!).
It's a Small World Holiday will soft open almost a week before the official holiday season start date, so I am guessing it will be open somewhere in the range of 11/6/15 (unless the 60th anniversary events affect it in any way).
Jingle Cruise will probably open when the season officially starts, or maybe a day or two earlier as a soft launch. I don't know if the holiday season will officially begin at the
expected time (which would be 11/12 or 11/13), or if there could be some sort of delay due to anything happening for Disneyland's 60th anniversary events.
The 3 Disney hotels' Christmas trees have been going up about 9 days before Thanksgiving for the last couple of years, but the giant gingerbread house in the Grand Californian Hotel lobby may not be fully ready to go until Thanksgiving. Santa Claus and the Christmas carolers don't appear at the hotels until Thanksgiving day and beyond, but Santa will be in the 2 parks and the Bell Ringers will be in California Adventure when the holiday season officially begins on or around 11/12 or 11/13-ish.