“Equivocation,” a Spreckels Performing Arts production onstage in Rohnert Park, is a seriocomedy with endless levels and disparate themes, all of which are delightfully exceptional. In its 2¾-hour running time, there are repeated examples of equivocation by circa 1605 Shakespearean-style characters, both whimsically and seriously drawn by playwright Bill Cain. It’s a fictional history detailing King James I’s Machiavellian right-hand man, Robert Cecil (played sneeringly evil by Zane Walters), who’s pitted against poor, mostly ethical actors. […]