There is only one Deputy Attorney General. You may be thinking of US Attorneys. Interim fills have been appointed by Sessions. The formal nomination and appointment of all positions subject to Senate confirmation is the president. He has of course delegated this all over the place (to Sessions for DOJ, to generals for military, and so on), and for DOJ/US attorney positions, typically input comes from outside the government, as well as from inside.
US Attorneys, yes, thank you. Apparantly nominating them is one of Rosensteins responsibilities. And he’s not being prompt.