Jay:
In response to your question of the 1929 Show Boat.
It is a part talkie version. It really is a hybrid of the stage musical and the novel. It mixes songs from the score and new songs written for the film.
Universal released the film,
from the imdb website
Universal had originally intended to release the part-talkie version with authentic black spirituals and work songs only. When they realized that this could potentially backfire on them, they obtained the rights to the Kern-Hammerstein musical, incorporated some of the score into the film, reshot two scenes so that Laura La Plante could "sing" (with a dubbed singing voice) two hits from the score of the Broadway show, and, finally, in desperation, filmed a two-reel prologue in which three stars from the stage version of "Show Boat" sang five numbers from the show, two of them being the ones that Ms. La Plante performed in the film. The strategy did not work, and the 1929 film version of "Show Boat" was not successful.
Some of the other songs not written by Kern and Hammerstein
"Down South"
(Ravenal's Theme Song)
Music by William H. Middleton
Lyrics by Sigmund Spaeth
Information on vocal not available
"Deep River"
Traditional
Sung by Eva Olivotti dubbing Laura La Plante
"I've Got Shoes"
Traditional
Sung by Eva Olivotti dubbing Laura La Plante
"Coon, Coon, Coon"
by Leo Friedman and Gene Jefferson
Sung by Eva Olivotti dubbing Laura La Plante
"Ol' Man River"
Sung by Eva Olivotti dubbing Laura La Plante
"Can't Help Lovin' Dat Man"
Sung by Eva Olivotti dubbing Laura La Plante
"The Lonesome Road"
Music by Nathaniel Shilkret
Lyrics by Gene Austin
Sung by Jules Bledsoe dubbing Stepin Fetchit