Doing further research, yes, the audio track remix should work. I'll post a clip in the next few days.

The process will involve DPL2 decoding the 2.0 participation track. The audience, which is only in the rear channels, would then be boosted and mixed into the rear channels of the 5.1 track. It should sound great when finished.

Also, it turns out the BluRay Vintage Callback subtitles are specifically a transcription of the 1983 Say It/Audience Participation Album. That's interesting.

I'd still like to get my hands on those subs, but have not been able to find them.

Finally, can anyone confirm or deny my current suspicion that the DVD's audience participation track IS the 1983 CD synced to the movie?