That's why we should just let the FBI and Inspector General do their jobs, without the Congressional clown show. Professional investigators will dig through this, layer by layer, until they have a complete picture. At that point, they will release the results as a definitive record. Congress demands instant gratification, regardless of whether their target has the information or not. This puts the target in a lose-lose. They either provide tentative information, knowing that it is subject to change, or they refuse to provide tentative information leading to allegations of stonewalling. Either way, Congresscritters will leak bits and pieces that suit their agenda, even though they've been cautioned that the target is still gathering information.
This new bit about maybe having some tapes is a good example of this (and reportedly was discovered during the IG investigation). The IRS has apparently discovered that not all backup tapes are always scratched after six months. They don't yet know what tapes, or what may be on those tapes, but only that some additional tapes exist. From the IG perspective, this is something to be further investigated, but is not for publication since they don't know what they have. For Congress, however, this incomplete tidbit is another chance to stoke the flames so they immediately leak it. Rinse and repeat, hundreds of times, and all Congress has accomplished is tainting the serious, professional investigations.
(And for the record, your list is a highly distorted, purely partisan spin on what has actually happened.)