If Madeleine was lifted by a predator it was done within a very tight time frame ... a very few minutes. There simply was no time for anyone to hang around with a body and there would have been many more areas of contamination to cause 'alerts'.
Did Eddie once even cast a glance at a door handle?
I firmly believe madeleine was alive when she left the apartment.
With reference to the DCI and his thoughts ... it is my opinion that the investigation latterly came into possession of intelligence which suggested the worst case scenario that Madeleine was dead. This had to be checked out ... and I believe that is why Tito and Muzzy checked out the mound area.
I like your line of thought, but I have to raise some questions.
The mound is not unimportant to Luz, as media reports intimated at the time. Quite the opposite, it is central, and an integral part of the traffic system, particularly the one way system. By this, I mean it is not quiet, it is fairly busy.
Changing tack, here is Kirsty Louise Maryann, childcare worker who participated in the search on 3 / 4 May 07.
"Questioned, the deponent states that beyond this situation, on another occasion, an event caught her attention. An individual of the male sex, in Praia da Luz, next to a café, whose name she does not know, was playing a guitar until the day of the facts, now under investigation. on the night Maddie disappeared and while she was involved with a group searching, mentioned prior, they encountered a vehicle, whose make and model she does not know, of while colour, commercial, parked on top of a hill, where, she cannot identify. At this point, some of the group elements banged on the window of the vehicle and the back doors and saw the person who habitually played the guitar on the beach. He was covered with blankets, reading a book and drinking a beer, with the help of a flashlight. Questioned, they did were not able to observe in detail the interior of the vehicle. She add that the individual was asked whether he had seen a minor of about four years of age and the same responded, jocularly, that on that night, no one knocked on the doors of his vehicle."
There are two areas within Luz where people park overnight their camper vans or, in this case, a Ford Escort van.
One is south of the Paraíso - not the restaurant, but the urbanisation immediately west of the mound. That area is flat as a pancake, so it can be ruled out.
The other is on top of the mound, up a hill that Kirsty had no reason to recognise.
Nor did SY, since they have not visited the crime scene, in any real sense.
For these reasons, I do not think that SY was working on intelligence. If I am gracious, I think they were working on nearness. If I am not, they were working on ignorance.