You are getting at a major undercurrent in the "remains have been found" event, by explicitly asking whether Dan got to the remains, handled them somehow, and then "found" them later. Dan is a very narcissistic kind of guy. If he did this, the most likely reason, In my opinion, is that he didn't want the world to see poor Esther had committed suicide: foremost because it would give the lie to the lalaland fantasy he has been trying to manipulate people into believing that the relationship was great and Esther was happy. To those many who pay attention to the gulf between what he says, what he does, and how he comes across, it is easy to conclude that Esther killed herself because of him, because he kept haranguing her, because he's a pathological narcissist and impossible to be around, because he destroyed her at the core. Many possibilities. But suicide for Esther would not fit with Dan's branding at all. So, he finds she has killed herself and destroys the evidence. Perhaps there were pills, perhaps other evidence. He might even have given the remains an extra shove, which resulted in their being in a more inaccessible location.
This is what I believe happened, from everything I see before my eyes, as well as paying attention to how police poke holes in his narrative. I believe Esther killed herself, Dan found the remains earlier, and did some rearranging to conceal a suicide. All an artificial construct. All for his branding.
I assume the police asked him earlier not to traipse around—they were royally ticked that he did so, plus he contaminated the entire search area—but the police made clear that he had decided he was going to do it anyway.
As the police pointed out, it was very strange that the skull fragment turned up suddenly in plain sight right next to the trail. They make very clear it wasn't there shortly before.
Yes. Absolutely that case. The Cody woman has no empathy, very much like the Esther guy who expresses no empathy for Esther, just how "sad" he is that she is no longer. Imagine being merely "sad" after more than half a life with a partner. And he feels oh, so sorry, for himself. I believe the Cody woman got 30 years.