2. There is no constitutional basis for a "temporary" appointment to a role that requires Senate confirmation unless the role is filled on a temporary basis by someone else who has already been confirmed by the Senate. This is why the internal DOJ succession chain for unexpected departures involves only DOJ officials who have been confirmed: Deputy AG, Associate AG, Solicitor General, and then a series of U.S. Attorneys in prominent districts.
The Senate is in recess for the Elections since the 2nd week of October, he can run it for 210 days.