Thank you for your input!
Basically I want to copy all of the skeleton bones, together with it's constraints. I'm recreating the skeleton within the same skeleton. I will use that second skeleton for mirrored movements.
Those are a bit complicated movements, not so ideal for Spine, so I will have to figure out a way to copy everything instead of manually recreating the mirrored movements.
So since when I copy all the bones the constraints are not copied with them, and the constraints apply only to the original bones, I have to recreate the constraints.
(actually moving constraints to a new skeleton can be achieved by re-importing the project itself as a second skeleton but that is not what I'm trying to do :p)
And yes, you're right! the "Linked" state with different values can be done by setting different values in settings mode without the linked state, and then in animation mode set the state to linked, thanks!