DR Jose, do you know this fantastic book about the making of the show? No one really knws how much of the Dream Ballet was done by whom. The original Hammerstein ballet called for a circus, with Aunt Eller as a bareback rider, as I recall, and DeMille told Hammerstein, "No young lady has a stupid dream like this; they dream about sex." She was contractually required to use music from the score, but she didn't bring Trude Rittmann in as dance arranger until her next show, "One Touch of Venus."
Russell Bennett most assuredly did a lot of the work on the ballet, since he scored it, but I think a lot of it was cobbled together for DeMille by her rehearsal pianist, whose name I've forgotten. He might be mentioned on one of the videos from North Carolina School of the Arts and he might also be mentioend in Steve Suskins book, since there's a lot in it about "Laurie Makes Up Her Mind."