You know CJ is right about this.
/shocked
Huh.... he he's not...
The President has the Constitutionally granted right to nominate whomever he damn well pleases for those positions, the Senate then either agrees or disagrees, and that's it. President Trump could nominate Mickey Mouse for the position and Congress would either have to agree, disagree or most likely just sit on their ***.
Recess appoints are temporary appointments meant to fill a position while Congress is out and then again Congress either agree's, disagree's or sits on their ***. The only thing different about this process is that if the Senate sits on their *** then the temporary appointment continues in their roll until the Senate gets off their ***.
The President has the authority to boot anyone within the Executive, that's what being head of the Executive means. He doesn't need Congressional approval to execute his Constitutionally granted powers.
This all just goes to show that Rosenstein was the Democrats inside guy all along, the fail safe plan.