All three targets can easily be lured onto the empty 1st floor if 47 approaches them disguised as the therapist.
Carmine DeSalvo can be killed by choking him with the barbell he uses.
Rudy Menzana can be killed by either poisoning the drink he hides in the globe or by placing and detonating a RU-AP mine on the chandelier holder on the 1st floor.
Lorenzo Lombardo often resides in his room on the 1st floor by himself. The guard by the door can be bypassed through the room next door. As Lombardo faces the balcony door, one might have to wait for him to turn around and attempt to leave before one can sneak up behind him for a silent kill. Alternatively one can just shoot him with a silenced weapon.