As the show was essentially a revue, there were no character names in the playbill, just a list of cast members. The list of musical numbers did not specify which cast members sang them.
During previews, the production played eight performances, but after the opening the production schedule changed to an unusual schedule of nine performances a week (Tuesday through Saturday evenings, matinees on Wednesday and Saturday, and two matinees, at 2 and 5, on Sundays). As the production opened on a Monday evening, that first week there was no performance on Tuesday. This nine-performance-a-week schedule explains why we list 18 performances for a two-week run.
We list the production as a Broadway production even though it appeared in the Off-Broadway ABCs in the New York Times. The theatre in which it played was sometimes classified as Broadway and sometimes as Off-Broadway. The Best Plays of 1976-1977 classifies the production as having been Broadway. Best Plays usually followed Variety in such matters. We generally look to Best Plays (and, by extension, to Variety) when there is some question as to whether a production should be classified as Broadway or Off-Broadway.