From my understanding, these are eventually something Nelson would like to do far down the line, so I’m more interested in what kind of idle animations people can think of. My only suggestion not tied to the actual animation occurring is that all sounds (if any) caused by idle animations should be client-side, in my opinion.
I don’t think “cracking knuckles” would look right, especially if it had sound to it, depending on how it’s done. I crack joints by interlocking my fingers and stretching them out, palms facing away. I think that’d probably look a bit more natural with the player model.