Board members now in charge of Disney World's governmental district include anti-"woke" activists and a major GOP donor.
One plaintiff falsely claimed that COVID-19 hasn't been proven to exist.
Union leaders said talks broke down over requiring guests to show proof of vaccination or a negative test.
The policy had been announced earlier this month, right before the Supreme Court blocked the OSHA vaccine mandate.
Universal Orlando's new vaccine-or-testing policy was based on an OSHA regulation now blocked by the Supreme Court.
Universal Orlando requiring workers to get COVID-19 vaccine or be tested weekly starting in February
The new policy matches a federal regulation that may be struck down by the U.S. Supreme Court.
The change to Universal Hollywood's COVID-19 policies is a result of a new L.A. County health order for "mega events."
Unvaccinated Universal team members are required to wear a face mask "at all times while on property."
The agreement covers the 43,000 employees represented by the Service Trades Council Union coalition.