I saw a cool thing on, I think, the History Channel (back when it was about history) where a cavalry carbine still held by a Sioux
was tracked, through records, archaeology, and comparison of shell casings dug up on the battlefield
from the name of the cavalryman to whom it was issued,
to the place on the battlefield where he likely died,
to where it was taken and used by a Sioux on another part of the battlefield.
They showed the carbine, and how it had been decorated by the Sioux with brass nails and engravings.
Fascinating stuff.
I remember that presentation. It was done by several forensics experts who looked at shells, bones etc. - basically everything you stated. It was very well done.
IIRC, there was an unspent .45-70 rifle shell found on Last Stand Hill that an historian was holding at the end of the episode. He got a bit teary-eyed thinking about the young immigrant on Last Stand Hill who probably came off a boat from Germany or Ireland the year before and ended up there in that hell-hole and probably lost the bullet in a last ditch effort to load his gun one final time.
Yes saw a forensic show about how the Indians would put any round in their guns as the bullets would topple thru the air causing massive wounds on targets.