PHOTOS BY JOHN POSADA From left, Alex Newell, Megan Kane, Pomme Koch (standing), Mark Evans (sitting), Allan K. Washington and Wesley Zurick co-star in “The Last Supper” at the South Orange Performing Arts Center. Five graduate students — all card-carrying liberals — share a house together, and enjoy having a big dinner together, every Sunday, talking about issues important to them. “We’ll bicker to the death, with our very last breath, and tonight we save the world,” they sing. “If we took just one Sunday off, humankind would perish.” One Sunday, though, they have an unexpected guest — Zack, …
