Select rides will be open 6 p.m. to 8 p.m. on Jan. 8 and 9 exclusively for pass members and Fun Card holders.
2021's new attraction lineup ranges from record-setting roller coasters to an immersive hotel experience.
Iron Gwazi will be the world's fastest and steepest hybrid coaster when it opens in 2021.
Aquatica San Diego will instead have one final operating season in 2021.
Theme park news: Universal parks lose $200 million / Rise of the Resistance change / BGT Christmas Town
Reopening Orlando and Japan parks with limited capacity has not turned a profit for Universal's theme park division.
The open jobs include positions for which SeaWorld had recently permanently laid off furloughed employees.
21-year-old Jacob Kaminsky, who died in an accident at the Orlando StarFlyer Monday, had worked on Busch Gardens' Iron Gwazi coaster.
Four of the 10 scare zones will be new for this year's event.
The event will feature only open-air scare zones and the "Fiends" stage show.