You have to change/lower the video bit rate in order to have a higher quality PCM soundtrack. You have to compromise somewhere and can't have both. I like the idea of making an "extended version" with the higher bitrate mono soundtrack. Methinks I'll do that. And yes, it would be dual-layered.
The Jaws The Revenge laserdisc DOES have the happy ending. The "regular" theatrical ending has never been put on on regular home video. Jaws The Revenge does pop up on TV quite often and any tv showing will have the regular theatrical ending along with the other additional footage. It would be easy to put a mask on that footage (since it was shot in Super 35) and get what was essentially the composition of the original footage in widescreen.