The limited reopening will not include any rides or attractions due to California's current COVID-19 rules.
The email came more than a month before the first Orange County inspection of Fun Spot's Orlando location.
Theme park presidents used words like "arbitrary" and "unachievable" to describe California's guidelines that would allow parks to reopen amid the COVID-19 pandemic.
The release comes after a month of verbal sparring between Disney, the theme park industry and Gov. Gavin Newsom.
Disney World is asking guests who can't wear a face mask to reschedule their visits for a later date.
The park will offer $99 annual passes for 2021, matching the price when the park opened in 2011.
The event will offer holiday stage shows, light displays, and seasonal food, with single-day tickets costing $20.
The deal comes after Disney agreed to provide free COVID-19 testing for employees, which had been a sticking point for some Disneyland unions.