I think Tom Sawyer Island will still be open next month...through January at least. My kids are also sad about the shooting gallery closing. The island closes early every day, like 4 or 5 pm.
My kids love the EPCOT scavenger hunts. The game board cost $10 but you get a little souvenir prize. I think there might be a DuckTales one for free, though.
There are boats that go from Disney Springs to some of the hotels, and a MK to Wilderness Lodge/Fort Wilderness boat. My kids like the horse barn at Fort Wilderness.
The best place to meet Stitch for us is the character breakfast at the Polynesian, if you can get a reservation.
There are still a couple of play areas in Epcot (1 outdoors and 1 space-themed) and an indoor circus themed one by the Dumbo ride. Epcot has a neat little model train display in the Germany area, the aquarium at the seas, and the Moana Journey of Water exhibit. Also you can collect postcards to color from each country in World Showcase.
AK has the Wilderness Explorer learning stations/activity books. We find that we do a lot of non-ride attractions because my kids have a hard time waiting in lines. We will do 1 long line a day and then have to keep everything else to shorter waits.
Epcot is our favorite, because we can still have a good day, even if it is crowded. There are a lot of neat displays to look at, like Norway had one about Nordic influences in Frozen or Marvel, there was one about a desert race (in Morocco), and in Japan, there was one about kawaii (where I learned Tom Nook in Animal Crossing is a tanuki, not a raccoon). I think they may switch the displays out from time to time, so I feel like I always see something new each time I go.