I don't honestly know. From Day 1, I never thought Heather drove to PTL or was even there. I've always felt like something started at the apartment, and all those subsequent calls were the M's trying to set Heather up after the fact as someone who was obsessed and trying to reach SM. I thought she was kidnapped and harmed much earlier on the timeline than those calls superficially suggest.
When the Longbeard's info was presented, that made even more sense. I'm not sure what SM knows and doesn't know. It could be that TM doesn't want him knowing all of Heather's fate because then he can't spill it. It could also be that he killed her under Tammy's engineering, so he can't ever tell anything, because all roads lead to his guilt. It could be that a third party killed her and he has seen that evidence, or witnessed it. Or, some other scenario. But I always felt that the state got in its own way by trying to marry the scenario of a kidnapping/murder at PTL to the fact that the car was simply found there. It seemed there were far more moving parts to this crime and I think the Longbeard portion punctuates that.
My tragic experience with a narcissist is such that if I haven't learned anything else, I've learned that with their stories, up is down, left is right, and over is under. The good news is, they reveal their acts in the stories if you're paying attention, and while there's just so much that's not known about Heather's fate, I think the truth is threaded here and there throughout the very words of both M's. Maybe that's what we can re-visit, and no, with this kind of personality, it's not nit-picking. They are telling parts of the crime in how they narrate to police and the public, in my opinion.
Sadly, I have long believed that Heather isn't recoverable, but I hold hope that Fate will provide a twist that only Fate can deliver, and the Elvis family will be able to have the homecoming and funeral they so need, however differently that may occur due to where and how Heather may have been left and the passage of time. I believe that's also what Debi was saying and we need to remember - hope is all anyone has and I hope with Heather's mother and the rest of her family that she can receive a laying to rest. And that the Moorer's and any aid to them can fully burn.