Respectfully snipped for focus and commentary response.
Yes. He didn't just take them to a random spot; it was chosen ahead of time. I speculate there is indeed a good possibility he had it staged.
Amateur opinion and speculation
It appears so, that he had it staged.
In addition, it appears he may have even staged things so as to implicate one or two people, by virtue of leaving evidence at the scene that may have pointed LE toward these 'other' potential suspects.
Could this be the reason for the wording at the presser, something to the effect of 'you never thought we would change investigative strategy'. Might LE have finally become wise to the killers attempt to throw them off?
Might the killer have dressed in disguise so as to resemble someone else, someone who has/had a sordid past, someone who could be framed?
Could it be that LE believes him to be from Delphi, or have worked there, or been born there, or lived there, could this belief be related to intimate knowledge the killer had of those who he wished to set up for the murders? Or possibly that the killer had been able to enter and exit the murder site, undetected, so as to set it all up?
If so, that would be quite some planning. Might it lead one to believe that the killings weren't random? Or perhaps they were, and the true motive was to frame/set up/do damage to someone else, someone in the community who the killer had a grudge against?
Or perhaps, might he, as a SK, use such methodologies as part of his M.O. to escape capture?
Lordy my thinker spins at this stuff.
All speculation, of course.