These are scoring sessions for the movie King Creole.
On February 20 1958, the motion picture musicians union went on strike. To get around this problem Hal Wallis decided to send the film to Mexico City for post-production work, hence the scoring sessions being held there. Because Paramount producer Walter Scharf was a member of the union, he couldn't couldn't be seen to be breaking the strike, so Hal Wallis oversaw these sessions personally, relaying daily updates to Walter Scharf over the phone each night.
The movie version of 'Steadfast, Loyal And
True' is the first verse of the song, then
repeated faster, and
was recorded on the movie set.
The movie version of 'New Orleans' contains additional vocals ("Where") by The Jordanaires, taken from Track "W", and finger-clicks recorded on the movie set.
The movie version of 'King Creole' contains a "Tommy Gun" drum overdub, a "Jew's Harp" effect guitar gliss, a guitar sweetener, and finger-clicks recorded on the movie set.
All timings in the 'Musical Breakdown' below are taken from the Blu-Ray release of the movie.
Thanks to David English for research.