Does theatre style apply to the albums below, and others like them? In both cases it looks like the album was recorded before the theatre work was premiered. Is this what the “demo cast” example in Style / Specific types of releases / Theatre - MusicBrainz means?
https://en.wikipedia.org/wiki/Randy_Newman's_Faust:
Randy Newman’s Faust first had a limited run at La Jolla Playhouse in San Diego in September 1995, which coincided with the release of a concept album version, featuring a different cast and arrangements than the stage version.
https://en.wikipedia.org/wiki/Jesus_Christ_Superstar:
Initially unable to get backing for a stage production, the composers released the score as a 1970 concept album, an immediate success which led to its Broadway stage debut in 1971.