Andrew Lippa's cult favorite met Charlie Rosen's Broadway Big Band.
Egan's one-woman show will take place on the Disney musical's 20th anniversary.
Mann joined in at Spector's A Little Help From My Friends cabaret show at 54 Below.
These performers will take the stage at the nightclub throughout the month of April.
The Drama Desk Awards will be held June 1 at the Town Hall.
The Broadway and television actress will perform five shows at 54 Below this May.
Spector plays a young version of Mann in the Broadway hit Beautiful — The Carole King Musical.
The gathering took place at 54 Below on March 22.
The Emmy winner and Broadway veteran will perform four concerts at 54 Below.