Historically, they have always done Holiday Wishes (replacing the 'regular' Wishes) and Holiday Parade (replacing the usual daytime parade), in addition to other MVMCP show offerings, during the week of Christmas (after the last MVMCP of the year).
Last year (2017), since Happily Ever After was new, they didn't show Holiday Wishes in the evenings and instead, they showed Happily Ever After.
This year (2018), it appears from the event schedule and hours of operation calendars that Holiday Wishes will return in place of HEA during Xmas week. This isn't 100% confirmed, but it appears to be the case.
Unfortunately, given the inconsistency of the last two years, it may be a little challenging for you to plan what is going to happen with 100% certainty. Happily Ever After is a fantastic nighttime show, but I wouldn't recommend blowing up your trip plans to see it. Either way, you are going to have a fun nighttime show... and who's to say they won't upgrade Holiday Wishes next year to something with more projection technology like HEA?