Saturday update. Picked up the rear axle from the salavage yard, pulled mine apart ( my brake shoes are 3.5" wide, does that mean my axle isn't original? ) then went to take the passenger side hub and axle out. Can get the drums off ( either side ), studs were bent. So, I tool the axle back to the yard and asked them to pull me another one and to be careful. So, now waiting till monday to hopefully pick up another axle to remove the hub and axle shaft and install on mine. Luckily this is a really simple job, once you have the right parts. To be continued...
TBH I suspected something wasn't original when you said, "because 1/2 ton suburbans have rear sway bars, my 2500 does not" because AFAIK all Suburbans got the rear sway bar. That's one reason the trucks don't show up as a direct donor for Suburban rear axle, because the trucks lack the rear sway bar mountings.
At any rate, it sounds now like you have the JB8 brakes since you're measuring 3.5" shoes. I kinda thought the drum you posted a pic of looked awfully familiar, the Jx7 drums are noticeably less deep.
However, it doesn't make any difference for the parts you're replacing (hub / axle), but it sounds like you bought a complete rear axle based on what you said about not being able to get it apart due to bent wheel studs?
If that's the case make sure you get hubs that are good, no one wants to have to replace wheel studs after they've purchased a used hub that should be good. For me I chose to replace studs because I knew my hub / bearings had 100k miles on them and I didn't know what the donor had on it or the maintenance of the other axle. I ended up extracting the studs from the used hub and reinstalling them in my original hub. I also like looking inside the original and seeing Timken on the bearings and I couldn't do that with the replacement from 2002.
Also be sure and post up some pics of the action! Everyone likes pics.
Steve