Minnie wasn't there until London.
From JRB in 2007:
Goodbye Newt, Hello Minnie. All that doubling and tripling of characters had some wonderful effects on the play, but sometimes it worked against us. We had only one actor (the wonderful Shaun Escoffery) playing the three black men in the show, Jim Conley, Newt Lee and Riley, the Governor’s driver. What we discovered during the first readthrough was that Jim Conley overwhelmed everything else: when Shaun had to switch from Conley back to Newt, it was always a letdown for the audience to watch this actor subdue all of the charisma we’d just seen. At the same time, we were severely underutilizing an enormous asset: Malinda Parris, who plays the role of Angela, maid to the Slatons. Angela really only exists to sing "A Rumblin' and A Rollin'" but it was obvious Malinda could do much more than we were asking of her. So Alfred and I decided it was finally time to let Minnie McKnight take the stage. Minnie was the domestic who worked for Leo and Lucille Frank, and she had an interesting part in the case (she was coerced into signing an affadavit that was certainly partially responsible for Leo’s indictment); we also enjoyed the dynamics that would come from having an intimate member of the household testify against Leo. So we replaced all of Newt’s testimony in the trial and his reprise in Act Two with a new piece for Minnie McKnight. And now we love having Minnie in the show – I can’t imagine that she wasn’t there all along.
"I shall stay until the wind changes."