Exalted trigger timing
The creatures enter the battlefield too late for their "exalted" abilities to trigger.  "Whenever [object] attacks" abilities only trigger when attackers are actually declared; as the newly un-exiled creatures were not on the battlefield at that time, their abilities did not trigger, and they cannot trigger after the event has already taken place.


  508.2a Abilities that trigger on a creature attacking trigger only at the point the creature is declared as an attacker.


Also, your opponent cannot change attackers after they have already been successfully declared, regardless of what step you're on.