It is an 'investigation' which has to adhere to evidentiary standards and protocols, or it is a partisan (which it is) fishing expedition.
No matter how you attempt to justify it, it is 'hearsay' evidence.
It's civil and not a trial. It's purpose is the figure out what happened and then pass laws to keep it from happening again and again. Just because a lot of criminal activity is being found and transferred to the AG doesn't change it's scope.
Since it's not criminal in nature hearsay and 3rd party testimony is allowed. You don't get to make the rules, the HOUSE has that responsibility. The only real thing, outside of sending information to the AG, that they can do is to do things like bring up internal charges against it's own members.
You want to play victim, I suggest you to after the AG which has real consequences.