Excellent work, truly--the best I've seen on this hilt.
Great to see the observations on the "wonky" emitter shroud details--I've always assumed that this was cut and finished by hand with a file and/or fine sandpaper, which would lead to the asymmetry. Even the more accurate Obi TPM replicas done in the past have idealized this detail and made it symmetrical, incorrectly.
Also, great observation on the grooves in the emitter shroud as well being done by an angled tool.
Regarding construction method, Option 1 seems to be more probable and in line with common understanding of how the prequel props were made. The Option 2 solid core mass would have required much more foresight on the propmaker's part. He would have had to start with that piece and work everything around to fit on it, or having made all other pieces, create that piece to fit them all together. As a machinist, making a prototype from a concept sketch, it would be easier to make the hilt in "chunks" or simplified pieces, while keeping the idea of assembling it all around a threaded rod later on.
On that note, I know your software is showing that the threaded rod is off center, but I would be hesitant to accept that without better evidence. I have an easier time believing that's simply a photographic distortion, than that the original had an off center rod, which would negate the entire theory of a centered threaded rod being what the hilt was built around. Is there any evidence of the rod being off center on any of the Qui-Gon or Maul props?
Great find on the LED bezels--those really look close, and better than I've been able to find. Can you PM me your source? The later three-hole emitter version of this hilt, the one with the red hemi, has chromed bezels, but on the Episode 1 prop, the bezels seem to match the finish of the surrounding aluminum. Your bezels have that look, being aluminum, I assume.
Regarding the presta valve... that is a discussion in itself. You have observed the 90 degree knurling, as I did, and you seem to have found the same type of valves I did as well a few years back. These valves are the closest that seem to be available now, but on the best reference photos showing the hemi valve, the threading is clearly visible on the inside around the hemi, and the surface of the valve shows evidence that it was ground down. So there seems to be a variation of this valve that was taller, that when ground down, created the flatter surface and immediate threading visible within. I'll have to post some pictures showing what I mean to better explain it. It's not an easy piece to find, but can be replicated easily IF the proper knurling tooling can be sourced or made.
Keep up the great work--can't wait to see more progress.