Downtown vets Taylor Mac and David Greenspan will appear in Classic Stage Company’s upcoming production of “A Midsummer Night’s Dream,” toplined by Bebe Neuwirth and Christina Ricci.Mac, the hyphenate whose rep in Gotham was establishd by shows including epic “The Lily’s Revenge,” will play central sprite Puck alongside Neuwirth, who stars as fairy queen Titania. Anthony Heald (“Love! Valour! Compassion!”) appears as Titania’s estranged husband, Oberon. Along with Ricci, the play’s young lovers will be portrayed by Jordan Dean, Halley Wegryn Gross and Nick Gehlfuss. Steven Skybell appears as the donkey-headed Bottom, with Greenspan playing a fellow laborer. Helmed by Tony Speciale, “Midsummer” is the latest in a string of star-driven stagings from CSC. Current offering “Galileo,” toplined by F. Murray Abraham, followed a much-lauded incarnation of “The Cherry Orchard” starring Dianne Wiest and John Turturro. “Midsummer” begins previews April 4, with an exact opening date still to be set.