https://soundcloud.com/labofhookers/...-piano-version

This version is more emotional, whereas the final cut became more of a triumph as Gaga wanted it to be that way.

The 'original version' is the demo with Diane's vocals right?

Gaga's vocals are on this 'original version', so this version already contains (some of) the changes to the lyrics/melody/composing/arrangement of the song

Maybe you're right, but I'm more going for the whole back and fourth Gaga and Diane had. Diane wanted the song to be really sad, and Gaga wanted the opposite.

This is not the 'original version'

This is the version that plays during the credits of The Haunting Grounds.

Diane did say her version was a sad piano ballad from start to the end so this was probably the finished version of the demo which they would ask gaga to record her vocals to complete the track?

Edit: wait slobro makes sense too

That is just a stripped down piano-only version used in one part of the movie.