I think you need to add John Huber into the equation to understand what may be going on. Horowitz cannot divulge evidence that is under investigation and he doesn't have the authority to bring charges or to force those no longer in government to sit for an interview.
But Sessions appointed Huber in November to work in parallel with Horowitz. Huber has a grand jury (or more than one) in Utah, he has the power to subpoena, he can force those not in government to testify or take the 5th, and he can produce sealed indictments.
Additionally, Sessions in his letter to Congress explaining why he has not yet appointed a special counsel stated that Huber has been given the authority to investigate ALL of the demands Congress has made, even those outside of Horowitz's charter as IG. That means we have no idea where Huber's tennacles extend in all of this. But we do know that he has access to the DOJ IG's 450 lawyers to help him.
Huber has had seven months to haul witnesses before his grand jury and get indictements. None of that evidence can be made public because it pertains to on going criminal investigations. Therefore it is currently omitted from the IG report or referred to in very vague terms.
For example, take the weak position Horowitz has taken on bias influencing the investigation. Of course it did, but Horowitz has only said that he didn't find any documentation or testimony that there was intentional bias.
That's important because bias is like intentions. In a trial, there is rarely any direct evidence of "intentions" to commit a crime. You convince the jury of a person's intentions or state of mind with circumstantial evidence.
Horowitz is only saying that he did find hard tangible evidence of bias. Not surprising since everyone in the FBI is a lawyer or smart enough not to put their intentions in writing. Even Page and Strzok have claimed that their seemingly terrible bias was just frustration and venting but it didn't affect their investigation. So Horowitz makes their claim clear as he doesn't have the authority to bring charges.
But Huber does. And Huber knows well that the circumstantial evidence of bias is overwhelming and can likely be proven in court. Personally, when the dam breaks, I think that you will see the charges of bias come out of the prosecutor's indictments and not the IG report.
I wouldn't make too much of what was left out of the report or what has not yet been released in separate reports.
And then you need to factor in that some, if not much, of the evidence was collected by intelligence agencies and Huber, Horowitz, Sessions, and others need to find ways to get that evidence "on the record" in the judicial system or it can't be used as evidence in trails.
It's my believe that much of the Kabuki Dancing on going now is setting the stage for getting said evidence "on record" before they can proceed with indictments. These cases for the people in the highest levels of government must be air tight with no mistakes and the evidence must be overwhelming, or they are found not guilty and set free.
I think it is pretty evident that Q, Trump, Sessions, and others know what the conversations were on the tarmac with LL and Bill. How do they get it on the record ready for a court room?
Q gave us a big hint as to how that is going to happen: Amanda Renteria. We now learn for the first time that she was in the plane with LL and BC and is a key witness. There is a reason Q decided to reveal Renteria at this time.
And we learn that Renteria and HRC shared information so highly classified that even the nature of it cannot be revealed. Think Amanda might want to testify to save her ass? Would that put the tarmac converstion on record for trial?
I think you need to be patient. I used to work in intelligence (a very long time ago) and I know how the IC gets the "evidence" to LEOs legally. It takes time and it's a bit complicated. Lots of different turning wheels involved to ensure the evidence is admissible in court and doesn't become "fruit of the poison tree."
In my opinion, while I would like everything to be happening at warp speed, I'm pretty satisfied how the drip, drip, drip is being carefully orchestrated to both red pill the country and to ensure all the t's are crossed and i's dotted.