I agree especially in JMs case. I truly think this was just another way for him to blend in and be seen as unassuming. A 'good guy' still going to church like his grandma probably raised him to do as a child growing up. Always wanting to keep up that front/mask that 'he was not the one' LE was looking for.
I watched JM very closely during his hearing in Texas and then of course we saw his mug shot. I didn't see one ounce of remorse in his eyes or behavior. I saw a cockiness, aloofness and icy coldness. Imo, he even smirked for his mug shot. This man has no conscience and I think that can be judged by past behavior. He rapes in 2002 and if he really was remorseful he wouldn't have gone on to rape another victim 9 months later.
And I don't think he genuinely had any remorse when he punched the lawyer in the jaw either. What he is good at is manipulating others so that he has the advantage. By pretending to be contrite he knew there was a very good chance the guy wouldn't press charges. That way he knew he was safe, for then anyhow, and his DNA wouldn't be entered into CODIS without an assault conviction. I believe that is why he got away with horrific violent crimes for as long as he did. JM could be as smooth as silk on the exterior when he needed to be but underneath he has no ability to have compassion and empathy for anyone especially his selected victims.
However; past environments during his childhood could be linked to where he has disposed of Hannah's body. Maybe it was an out of the way very rural country church. Maybe the church is no longer standing but old graves are still there.
Wherever his 'bone yard' is it is personally connected to him somehow. The problem with JM though he has lived in that area all of his life and trying to find that area and why he would select it over others is unknown even to the profilers that I know must be assisting Longo and the teams as they search. IMO.