My scenarios are:
1) Ron was fighting with Misty and Haleigh got in the way; Ron hit or pushed Haleigh and she suffered injuries that were not immediately apparent, i.e., "she was doing fine" that evening. Her condition took a turn for the worse probably by 9 or 10 PM. I do not think it was much later than that because I feel the cover-up and staging required some time to be accomplished effectively. If this scenario is close to what happened, it could explain Ron's fear of being implicated, which would explain his subsequent involvement in the cover-up.
2) Revenge/Retaliation: It seems reasonable to consider that someone wanted revenge against Ron. He had snitched his way through life to save his own azz; perhaps his snitching put someone behind bars for a long time, or cost someone their life. A relative or close ally of that person could have sworn revenge. Given his lifestyle, Ron may have crossed paths with an individual or a group that would not hesitate to do whatever was necessary for revenge. Might they have known the best way to exact revenge against Ronald Cummings was by attacking "his heart"?
My immediate thought on the morning of February 10th after seeing Misty appear teary-eyed on TV going over her timeline of the night before was that Haleigh had died accidentally, Misty panicked and covered it up. Over the next few days, it seemed probable that Misty might have gone off on Haleigh in anger and she died as a result. Misty's account of being asleep when Haleigh disappeared did not ring true for even a minute. There were too many red flags in Misty's posture, her voice, and her choice of words. Her account sounded more like memorized words than memory of events.
Then I studied the 911 call and my thoughts switched from Misty to Ron.
Ron "was at work" and, even though we have never seen anything that verifies his work hours, I do believe he was at work when Haleigh died. But this does not exonerate him, imo.
I believe when Ron found out about Haleigh he was truly devastated. I do not think Ron deliberately did anything to cause her demise, and I believe some of his ranting heard on the 911 call to be genuine grief. However, in the middle of emotional outburst and threats of killing whoever "stole" his daughter, I hear fear. I believe many things were going through Ron's mind--one being that he might in some way be responsible for what happened.
I doubt Misty killed Haleigh. Ron would not let her get away with that; he would have beat the carp out of her to find that out, imo. I believe the same holds for Tommy, Timmy, and Joe. I just cannot wrap my mind around the idea that any of the Croslins or JO did this crime and Ron did not have an inkling. I have a huge problem with the story of JO did the deed and Tommy and Misty kept quiet out of fear, partly because JO seems hardly a threat living so far away, but mostly because it does not explain Ron's involvement. And Ron's behavior after Haleigh went missing screams of his involvement, imo.
If this was not revenge/retaliation, I believe Haleigh could be the victim of discipline gone wrong--discipline administered before Ron left for work--which explains his part in the cover-up. Ron refused to allow anyone to delve into his personal life, even if it hindered the investigation. We also have Ratgate, Ron's attempts to forbid Misty to even have phone contact with Timmy after he had moved to MA, and Ron's continued alliance with Misty up until the time they were arrested on drug charges. There are far too many red flags in Ron's behavior to be ignored. At times he appeared to be a grieving father, but more often he appeared to be a man with something major to hide.
I am still not able to let go of a revenge scenario. This scenario could explain the fear factor that Misty and Tommy talk about currently. I cannot fathom any of the players living in constant and continuing fear of Cousin Joe, so maybe there was someone else at the MH that February night--someone sinister and truly threatening. It has been mentioned that Misty had been threatened with a gun in her mouth not to talk. Misty said this was a rumor, that it never happened, and went on to say that even if it had happened she would not be afraid, she would still talk. But I wonder...