FIRE these asses!
Sounds like grounds to me. Or do the ‘afscme’ or some other fed workers commie org, uh I mean union represent them.
Insubordination is one of the things that is virtually an automatic firing.
No need to fire them, ask if they wish reassignment to another agency, or if they consider early retirement as an option.
If yes to either, then outplace them, or place them outside. The office is moving, with or without them.
This is not, after all, the first move ever to decentralization.
And their severance package should be 1 red stapler. Let them play musical chairs to see who gets it.