Long overdue UPDATE
~ I’ve gotten ahold of 2 ISOs of the 2003 Platinum Edition DVD release, which includes the 5.1 audio of both the “theatrical” mix and the Enhanced Home Theater mix, which according to an extra on Disc 2, is derived off of the 2002 IMAX mix but optimized for a home theater setup. TonyWDA, I can confirm that the 5.1 theatrical track on the DVD is a very close match to the 1995 Laserdisc 5.1 like you’ve said, which is a huge plus. Speaking of which…
~ New rips of the 1995 Deluxe CAV Letterboxed Laserdisc tracks, both the PCM stereo, and the AC-3 5.1, have been precisely ripped by Archive.org user, Noogai3, or more familiarly known elsewhere as Infomaniac95, are publicly and readily available for use under their permission, which is pretty great to have.
With these sources, I could theoretically get back on track and continue the project, yet due to personal life going on generally, along with Christmas being on the way in a few weeks, I can’t exactly do so as soon as I’d prefer. Even putting that aside, I’d now need to seek out video sources for optimal visual parity, mainly the 2011 Diamond Edition or the 2017 Signature Collection Blu-ray, although other alternatives would be acceptable if they’re rendered and encoded well like a decent HDTV rip pre-dating 2011.