Presscoins.com is reporting that as of December 27 the new 2018 coins have already been placed at the All Star Resorts and Animal Kingdom. It is expected there will be 15 coins again (8 pennies, 7 quarters) in the same locations, but the quarter machine found in 2017 at the Stage One store (near the Muppets show) is currently unavailable due to construction. Since Disney did a good job with the dated coins in the past, we expect the machine will be moved somewhere else.
Meanwhile, in California the holiday nickel sets are on stage at Disneyland and California Adventure, reports Parkpennies.com.
UPDATE: Presscoins.com reports that, as of January 2, three 2018 coins were not yet on-stage: the Grand Floridian 2nd-floor lobby (penny), the Rock Around the Shop store at Rock ‘n’ Roller Coaster (penny), and the quarter machine at Stage 1 Company Store (the “Muppets” store), which is closed off behind a construction wall.