The Senate had to approve of Mueller extending his term beyond the 10 year limitation. An extension isn’t a second full term, but why spoil the story when you’re on a roll. Always entertaining to read the latest from neverTrumpland.
Maybe not, but it completely disproves your claim that he was limited to ten years max, when all it takes is a Senate vote to go beyond that. And the Senate is the body that approves the FBI director position, in case you didn't know, so it would likely be nothing more than a normal procedure.