Are you using PCM or AC3 for the various stereo and mono tracks? There's probably no need for both, since the uncompressed files should work with pretty much any player out there, hardware or software. The only limitation of this would be that any level adjustment, for the sake of having the dialogue at the same volume in all tracks, would have to be done manually in an audio editing program, since it's basically just plain audio without any of the metadata bells and whistles that AC3 can carry with it, so Dialogue Normalization isn't available for PCM.

I recommend leaving the level of the 1993 mix exactly as it is, since it's the most powerful version and it would be best to have it play back at the same level as it does on the laserdisc. The 5.1 will be at this exact same level, since the 1993 mix is its primary source and it hasn't been altered in this respect. Belbucus' 1977 stereo capture is also level-matched to this as well (the file that says 'reference level'), so this leaves only the mono version in need of adjustment to come out the same. Based on a quick RMS measurement I made of it a while back, I would estimate that a reduction of about -5 db would get the dialogue of the mono mix in the vicinity of the others, but I have not yet had time to make a more thorough analysis, so this may not be an accurate value.

Anyone wanting to use the digital stereo mix should reduce it by -4 db to match the other tracks—that's how much I had to lower it to get it to fit into the 5.1 mix.

I haven't got any of the others being talked about, though, so I can't speak for them.