"1936 Showboat has Irene Dunne and Helen Morgan, et al. It is indeed far superior (excepting the "galavanting around" blackface number that Irene does in the 1936 version...*shudders*)" Why shudder? This number is very typical of the kind of olio routine that would have been seen on show boats in the 1880s.
Hammerstein always intended the number to reappear at the end of the movie done by Kim and the cast of her play, first as a traditional dance then as a hot jazz number. In teh final editing all the modern section was cut, diluting the point but if you listen you still hear the tune unserscoring the first part of the dance.
The 1936 SHOW BOAT is as close as we will ever get to a document of the original production. Wasn't there supposed to be a boxed DVD set containing all 3 SHOW BOAT films?
Cast albums are NOT "soundtracks."
Live theatre does not use a "soundtrack." If it did, it wouldn't be live theatre!
I host a weekly one-hour radio program featuring cast album selections as well as songs by cabaret, jazz and theatre artists. The program, FRONT ROW CENTRE is heard Sundays 9 to 10 am and also Saturdays from 8 to 9 am (eastern times) on www.proudfm.com