1 - The actual Omni book only has two complete versions of "After Antietam", I see what they show on their site, but this is the breakdown in the book and what it all means:
1M2R Intro (Original) - The "R" leads me to this this is what they meant on their site as "After Antietam (Revised)". This is simply an alternate introduction to the cue "After Antietam" and only lasts for 6 bars. It features the "Reflection Motif" as Omni names it, a rising and falling figure in the strings. This theme itself can be identified at 1:17 in track 2 on the LLL presentation, just for reference. This cue is unused and not in any recording we have. That leads us to the next cue....
1M2 After Antietam (With Film Intro) - This is the one that lines up with the recording on track 2 of the LLL film presentation. It features a new 6 bar introduction that replaced 1M2R. Those 6 bars feature no melody, but the two chords in it are based on the first two notes of the "Reflection Motif". This 6 bar intro is NOT on the LLL disc, I don't know if it's in the film or not. The LLL presentation (and the OST) start on bar 7 of this cue, when the choir enters. Other than missing the 6 bar intro, the LLL matches this cue exactly.
1M2ALT After Antietam - This is a shortened version of 1M2, which is 52 bars. 1M2ALT is only 13 bars and would have faded out earlier. Its instrumentation is different - pulled back and scored for a smaller ensemble, 2 clarinets, trumpet solo, timpani, percussion, boys and men's choir. The trumpet/bugle calls in this version different from the ones we hear in 1M2.
It is also worth noting that the OST version of "After Antietam" does not appear in the Omni book, so there is indeed another version yet. The OST features different trumpet calls that don't appear in any version in the book and different rhythms in the melody.
2 - The Omni book has "1M4R Flashback (Film Version)" and "1M4 Flashback Version 2".
"1M4R Flashback (Film Version)" - This is written as the first 12 bars of "Drei Klavierstücke" (disc 1, track 21). The cue we hear on track 3 of the album overlays for 3 bars starting in bar 10 before continuing along on its own, the source music fading out. The source music returns during the final bar of the chorus, so it overlays with the last bar of the track.
"1M4 Flashback Version 2" - This matches Disc 2, Track 14 "Flashback Alternate 1". The other alternate is not featured in the book.
3 - You are correct on how that lines up, yes. The only difference is the Film Mix in LLL 1-24 does not include the orchestra entrance, and gradually fades out the field drums.
4 - Okay, so "54th Regiment" is partially source music and partially "Worth a Life". "Hoist the Flag", LLL 1-25, is present throughout the cue, albeit with repeated phrases that are not represented in the written music for "54th Regiment". "Worth a Life" overlays with the "Hoist the Flag" tune, and so it actually shares slate numbers. The contents on the Omni website are listed differently than they are in the book, "Worth a Life" is actually the "Parade Overlays" listed on the site.
This is complicated and a bit of a mess...so I'm going to just explain what we have on the CD first then follow up with what's in the book:
LLL 1-10 "Worth a Life" - This appears in the Omni book as "6M2 Worth a Life Version 2".
LLL 2-15 "Worth a Life (Alternate 1)" - This appears in the Omni book as "6M2 Worth a Life Version 1 (Parade Overlay)"
LLL 2-17 "Worth a Life (Alternate 2)" - This appears in the Omni book as "6M2 Worth a Life Version 2". It seems to be musically the same as LLL 1-10, so any differences must be only slight instrumentation changes or the pacing of the take. For example, at the climax in bar 12 the alternate takes a brisker tempo and the fadeout at the end takes longer. But musically everything seems the same.
Now here's some fun stuff from the Omni book to make things more complicated:
"6M2/6M3 Hoist the Flag" - This matches LLL 1-25 "Hoist the Flag".
"6M2/6M3RA 54th Regiment (Film Version)" - "Hoist the Flag" beings the cue, with orchestra beginning at bar 53. The structure of "Hoist the Flag" differs from any recording we have. When the orchestra begins it starts similarly to "6M2 Worth a Life Version 2", however the melody at the beginning is elongated. Structurally it features the same themes in the same sequence, again just elongated. We do not have a recording of this as far as I can tell.
"6M2/6M3R 54th Regiment" - Again starts with a version of "Hoist the Flag", followed by an orchestra entrance at bar 57. Again, basically structured the same but with different variations of the themes presented in all versions of "Worth a Life". Again, we do not have a recording of this as far as I can tell.
"6M2 Worth a Life Version 1 (Parade Overlay)" - As said above, matches LLL 2-15 "Worth a Life (Alternate 1)".
"6M2 Worth a Life Version 2" - As said above, this seems to match BOTH LLL 1-10 "Worth a Life" AND LLL 2-17 "Worth a Life (Alternate 2)".
So...there is a lot going on with that cue. Hope that all helps @Jay, and doesn't complicate things further! 🤣