My question would be, why would Tommy make up those stories about cousin Joe killing Haleigh and then forcing Tommy to go with him to dump her in the river? I cannot think of one logical reason why Tommy would lie to protect Ron. Misty might protect him, but no one else in the Croslin family seems to care that much about him. And why would Tommy say something that implicated himself if he knew the truth would point to someone else? He would have to have been paid a great deal of money or afraid for his life, one or the other.
I very much doubt that Ron shot Haleigh, even accidentally. I can't see a guy who knows guns so well even firing off a shot if his beloved daughter was anywhere close, that makes no sense to me at all. Especially considering that it would leave pretty clear evidence wherever it happened. The Croslin's house at the time was not in some remote wooded area, was it? I'm sure there were other houses close by, somebody would have heard a gunshot and reported it, and there would have been screaming, no doubt. And even if it could have happened, what would guarantee that Tommy or Misty wouldn't talk? Well, Ron married Misty, but then he divorced her in 6 months, so wouldn't he have been a little worried that she might turn on him??
Ron's family is not wealthy or powerful, and I very much doubt if they've got the entire SO as well as the FBI and FDLE in their back pocket, so IF that theory was even remotely possible, I think it would have been uncovered by now. JMHO.
I know a lot of you believe it, but this theory just doesn't have much merit to me, I can't make the pieces fit. Sorry.