"Integrity is crucial in an investigation, as you say, but my concern from the beginning is why did the DA write it all off with a flip '...not even a suspicion...' It appears that even with substantial circumstantial support regarding Holliday's involvement, the DA was not interested in pursuing the matter."
At this point, I think it is clear (as mud) that we don't really know who the witnesses were that the D.A. questioned. An interview almost fifty years after the event should be taken seriously, but not taken as gospel.
"Regarding Ike's testimony, was he directly asked about if he and the McLaurys had been witnesses?"
No, Ike wasn't directly asked that question. However, on the one of the points that you and I actually agree on about Ike, he was very intelligent and would have realized that, if he and the McLaurys had been eyewitnesses to Doc being in the vicinity of the attempted robbery and double murder and had, in fact, previously testified about it in court, he would have found a way to mention it in his testimony. His entire premise was that the reason Earps and Holliday "attacked" was because they wanted to get him out of the way because they had told him of their involvement, not because they had been eyewitnesses to suspicious activities on Doc's part.
Previous to this testimony, Ike had apparently given Will McLaury another reason, as Will had writen in a letter that Billy Clanton"... knew of the facts of the attempted robbery and told his brother J.I. Clanton and Thos and Robt (McLaury) and they had got up the facts intending to prosecute him Holliday and the Earp Bros. and Holliday had information of it." This information could only have come from Ike, since Billy, Tom and Robt.(Frank) were all dead. Without getting into whether this was actually the case, if it were true, it would mean Ike, or the McLaurys had not already made this information public (in other words, none of them had previously testified at the July hearing) and nothing is said about any of them being eyewitnesses. One could make the case that since the initial info is supposed to have come from Billy, that perhaps he was an eyewitness, but that's not what is said and if that were the case, why would he not have testified at the hearing that Vaughn lists Ike, Tom and Frank as witnesses?
"And why does Doc's approaching Ike about his concern over the whereabouts of his associates come off as 'an unbelievable story?' Doc drank and Doc was worried and he apparently talked too much."
Actually, you have a point, Joyce. There is one situation in which it would be believable for Doc to tell Ike he had participated in the attempted robbery and double murder: that he was in fact oe of the would be robbers (for which there is no real evidence) and that he knew confessing such to Ike was safe to do because Ike was part of the same criminal gang that Doc's collegues were also members of. Even drunk, which Doc may have been most of the time, he would never have made such a confession to an upstanding, reputable, honest rancher, because one would assume that a citizen of that character would have immediately contacted the authorities with information about one of the most horrendous crimes ever committed in Cochise County.
"It goes without saying at this point that the Prosecution attorneys were asleep at the switch. If, in going over testimony, you were to just follow the lack of input on the side of those attorneys, you might get a little different picture."
I doubt that Will McLaury was asleep at the wheel, having just lost two brothers I think he was wide awake, maybe too much so. If my chronology is right, he wrote the letter quoted above before Ike's testimony about Doc confessing to him. I believe it is possible that Will McLaury is who convinced Ike to abandon his original narrative because, even if it was true, Billy, who supposed came up with the original facts (if they were facts), was dead, as were Frank and Tom. Much better to have a live witness who had information directly from Doc regarding his guilt of murder. I think the whole thing backfired on Ike in two ways. Either one found his story unbelievable, as Spicer apparently did, or if one believed it, it also indicted Ike as in league with a gang of murderers and robbers, who one of those murders felt safe in confessing the homicide of Bud Philpot to.
"So it seems there are no answers as witness testimony cannot be trusted so there was really no point in having a Hearing. That leaves us with nothing to talk about."
Say it ain't so, Joyce!