Its production of “Blues in the Night” was involved in all five of the nominations, including Iyona Blake for Outstanding Lead Actress in a Musical, Matt Conner for Outstanding Direction in a Musical, Walter ‘Bobby’ McCoy for Outstanding Musical Director, and the whole troupe for Outstanding Ensemble in a Musical and Outstanding Production in a Musical. Another Cauldron production featuring Blake and directed by Conner opens this weekend, “Lady Day at Emerson’s Bar and Grill,” recounting the legacy of Billie Holiday.