re: Dreamgirls: Differences between Movie and Musical?
My comment re late 70s instrumentation similar to Salsoul was based on observations made by someone on musicals.net and imdb. Steppin' onstage apparently sounded a bit like it came from the MFSB stable and as it occurs in about 1963, the scoring is 10 years too late. Hence the film took the song toward gospel inflections rather than disco. Also, One Night Only is better placed in about 1974/1975 as it more closely matches when disco grooves came in (cf The Joy of Disco, BBC).