I love this funny find.
During the heyday of the swing era Whitey had multiple troupes of dancers so they could perform in different venues simultaneously (for example that's why Frankie wasn't in "Day at the Races", his team was performing at the Cotton Club). So when they mention "Whitey's Jitterbugs" it's hard to know who they are talking about. I tracked down the original playbill and "Whitey's Jitterbugs" in the cast of "Swingin' The Dream" were:
Dottiemae Johnson and Frank Manning, Beatrice Elam and George Greenidge [sic], Willa Crawford and William Downes, Joyce Boyd and Joseph Daniels, Wilhelmina Moore and Billy Williams, Anne Johnson and Thomas Lee, Norma Miller and Thomas Washington, Lucille Middleton and Joe Riddick, Emily McCloud and Samuel Pierce, Francis Jones and James Outlaw, Hilda Bess and Richard Bess, Joyce James and Leroy Jones, Arlyne Evans and Lonnie Jenkins
You'll recognize some of the names here, though I found it interesting to see who was paired with who. Also worth mentioning is seven flights is a lot at any time but they would have just danced hard! Maybe they didn't want to take the elevator cause there were so many of them and they wouldn't fit :)
From The Afro-American newspaper (national edition) November 18th, 1939