I suggest to try following,
Select an appropriate with Piano and/or Guitar in the style.
In Mixer you can change these where playing chords into organ voices, evt also change bass into an organ bass, change volumes of the tracks and mute other voices untill you found the style sound reasonable as TheaterOrgan style. Save this result in Style Editor into user memory or HD. Then also change the ots voices into Organ voices, and the save the style another time.
You may check what has been used in other Theater Organ styles as example.
May be not the really pro style, but certainly good usable.