“As an initial analytical point, referring to Mueller as unlawfully-appointed is an out-of-character own-goal here by Concord Managements attorneys. Muellers appointment is certainly lawful in and of itself and thats not really a serious point of contention.”
Wrong. The special counsel regulations say that the SC cannot have any personal relationship with any potential witness or principal to the investigation. If so he must (not should) recuse himself. Mueller has multiple personal conflicts of interest with just about everyone involved,starting with his protégé Comey, whose daughter he is godfather to.
Even if Comey has an immmunity deal from the Obama DOJ I don't see what prevents him from testifying. Not to mention that, given that Mueller and Comey are buddies, common sense should impel Mueller's recusal.