10-4 on all of above. AJMBLAZER helped to clarify some items as the terms I was using weren't correlating. My bad. Also thank you for the differential diagram as it definitely helps to better understand the inner CV joint mating components.
Regarding the difference in the Trail Boss axles, the only evidence I have of differences is from this forum. Like you I've seen that the axle length is different. On a separate forum that was specific to the GM Factory Suspension Lift it was mentioned by a member that the inner CV Joint housing (maybe outer ring?) was also a different diameter. I don't have evidence if that is accurate.
Regarding the actual noise source then, has it been root-caused to the stub shaft mating to the cross-pin? Because if it is then some members commented that a differential swap didn't fix the issue. I imagine the stub shaft would be replaced with a differential swap, but maybe its possible that its reused in the swap. Also, it would be dang frustrating if a fix is out there and GM Engineering still isn't authorizing it.
Do you have the jingle-jingle noise also and have resolved it with a stub shaft replacement?
For now (the past 5 days) the issue seems to be gone with the cv axle swap. Hopefully it stays that way. By the way, I've attached a link to a video of the noise I have (don't have time to compress to post). The dealer had confirmed this as the jingle-jingle noise, but I would like to hear your thoughts on if it is similar to others experiences.
https://photos.app.goo.gl/gZeLBcXCUWGS5rYw5