IMO; this scenario is plausible, because, according to MG, BM sounded frantic. Freak out mode.
What to do....what to do....must get rid of this body.
Somebody in FO mode, wouldn't be considering the implications of using a woodchipper, and all of the millions of pieces of evidence it will produce. If in face BM was in the middle of panic, he would be making hasty decisions. Or, driving around in circles trying to come up with a body disposal site. IMO, IF it was a heat of the moment homicide.
Premeditated? Still possibly panic mode. His anxiety levels and vitals will still be through the roof, even while trying to follow through on his plans. No longer Mr Calm & Cool. JMO of course.
Also....IMO.....BM had possibly come across many many abandoned mine shafts that were accessible. He would have/could have, already made that discovery in one of his previous hunting trips. Guy, out in the great vast mountains-legit hunting of course- stumbles upon a previous mine access/shaft. Hmmm.
Number 5. Hmm. What could it possibly refer to(?) Only LE and BM would know of course. I think CM brought it up just to shake up BM. It apparently hasn't been a confirmed piece of evidence. Yet. Who knows.
Did he get "lucky". I suspect luck more than his being a very good perp at hiding a body. Selling the PP property didn't seem to phase him. Nor the other newly acquired property. So, IMO, she is in neither of those places.
Of course, I believe, it was critical to mis-direct. Look here. Not there. "It wasn't ME".
This is all just my own opinion. After months now of following along on the case. How it develops. Reading here. And there. Waiting to see what the outcome will eventually be. So many perps, make a major mistake in the end. Something.....critical...they were not aware of or had even considered.
Just my own speculation.
MOO JMO IMO