Raubahns Arm

[LineageRazor]

what happened to Raubahn's original arm?

While the game never said one way or another, in real life amputated limbs are typically incinerated, so without other evidence, that's likely what happened here, as well. However, a quick Google search revealed that in real life patients ARE allowed to do what they please with their separated limbs, so long as doing so does not create a public health concern - so, assuming the same holds true here, the other options you listed are technically on the table!