Dozens of Casa Bonita workers on Friday voted to unionize, adding muscle to their requests for more protections, better pay and other concerns that performers have shared in recent months. About 80 cliff divers, magicians, actors, puppeteers and others at the Mexican eatery — which was bought by “South Park” creators Trey Parker and Matt Stone and upgraded to the tune of $40 million — are now represented by the Actors’ Equity Association and International Alliance of Theatrical Stage Employees (IATSE) Local 7, according to a union statement. They unanimously voted to unionized in order to address concerns in front of and behind the stage, as well as negotiate for better compensation.