Rather than firing Mueller, someone should start disbarment proceedings against him. Once disbarred, he will have to resign his special prosecutor position and then he can be fired for cause and stripped of any federal pension or benefits.
If and I suspect it will be easy for Cohen to prove he was in LA, then he and others need to go after Mueller in a way that neuters him without looking to the public that it is obstruction of justice, but that it is justice being served.
the best way to neuter mueller would involve the use of a dull butter knife
Mueller's motives are self-protection rather than ideological.