John Pankow and David Pittu are among the thesps lined up for the Manhattan Theater Club’s Off Broadway production of “Equivocation.”Pankow (“Mad About You”) will play Shakespeare (called Shag) in Bill Cain’s play, which tells a fictional story in which King James’ right-hand man (Pittu) commissions the Bard to write about the 1605 Gunpowder Plot. Cast, helmed by Garry Hynes (“The Beauty Queen of Leenane”). also includes Remy Auberjonois, Michael Countryman, David Furr and Charlotte Parry. Equivocation” has acquired some good buzz from earlier productions in Ashland, Ore. and Los Angeles. MTC incarnation begins previews Feb. 9 ahead of a March 2 opening.