We know the DOJ is corrupt and also see people being taken off their jobs there. You’re correct though that the ones who are lovin Sessions now are the who’s who of skunks. Now ask yourself, how did that come to be?
Only an employee can be deposed/questioned by the IG. If they resign or are fired, they are beyond the legal reach of the IG.
Huber will build evidentiary cases for referral based on Horowitz’s reports which is created from interviews of DoJ employees.
Optics also play a role. Some MUST be left in their positions to placate the enemy.