The only relations of events from that day I've seen or read was Alec Baldwin's interview, I believe with ABC News, shortly after the tragedy occurred. He related how they were performing rehearsals, during which he adjusted the cylinder of the gun several times, etc. The only contradictory information I saw was the FBI's initial assessment that the gun was sound and could have only discharged via a trigger pull.
Later, as in this recent news, further investigations apparently applied more scrutiny and found that the FBI's assessment of the weapon was in error. This new evidence was compelling enough to the prosecution that they dropped all charges. On ABC News yesterday they showed clips from the rehearsal that Baldwin related in his original interview, and these clips corroborate his recollection of events (they show him sitting in front of a camera adjusting the gun in the same manner in which he related during his interview last year).
If you know of additional testimony claiming that any of that is incorrect, that these investigators are lying or incorrect in their findings regarding the firearm, or that the video of the rehearsals were somehow doctored, I'd like to see it. It looks to me to be copacetic, innocent until proven guilty, etc. I see no reason to doubt Baldwin's recollection of events given everything I've seen and read, and the prosecution doesn't either.
Edit: I see the armorer and her lawyer claim Baldwin violated some kind of safety rule regarding pointing a gun at someone on set, but I can't locate a list of these rules (apparently there's four of them according to your quote?), any sort of validation that they're official, or evidence that Baldwin actually did what they claim.