In CA a company pretty much has to give multiple talks about the same subject before they can fire someone, unless they're within their 90 day period.
Actually, California is a "Right to Work" state, which means that an employer can terminate an employee at any time for almost any reason. The only exception is that an employee can not be fired as a direct result of being a protected class (Because of physical ability, religion, race, sex, etc). If multiple people were all fired and it does not appear that it had anything to do with their race, sex, etc., then Disney is well within their rights to let them go (at least according to state law).
According to here anad this lawsuit CA is an at will state not a right to work one.