Haunted Mansion always closes the first day after the Christmas season and is usually back up and running within a couple weeks unless there is a longer refurbishment tacked on. Splash Mountain and Grizzly River Run often close in the winter for some period of time for their annual refurbishments. The Paradise Pier re-theme was announced at D23 and then again more recently on the Disney Parks blog. The California Screamin' update is going to be a re-theme to The Incredibles. They put summer 2018 since they don't have a firm date yet. My guess is they are shooting for Memorial Day or at the latest the summer release of the new Incredibles movie. The rest of the pier stuff is supposed to be ready by then as well but may be sooner since some of the Pixar stuff kicks off in the spring.
Expect more refurbs to be added to that list. Clearly those are only the things starting January 8. There will be additional overlap since we know It's a Small World will go down later in January to remove the holiday overlay. There is also the update coming to Pirates of the Caribbean for which Disney has not given a date, but between January and May would seem a likely time. And who knows what else they might be planning to work on?