" he had been working on playing Charles Darnay in rehearsals for the forthcoming A Tale of Two Cities musical..."
How do you work on playing Charles Darnay in rehearsals? Was he cast in the role? Was he understudying the role? Was he thinking of auditioning for the role? I don't understand the phrase, I guess.
I'm not sure of the exact time line, but I suspect that he was not asked to "come to Broadway" with the show. I noticed his name was conspicuously absent from the initial press releases for the Broadway run of the show. However, he still can be seen in the promo pics that are on display at the Hirshfeld.
As for the show itself, well... It's a true "first-timers" project, and some of the clips I've heard do sound a bit green. For better or worse.