I think that's plausible.
The fact that the children were alone in the apartment (every night) for me, is a big part of the whole puzzle and a contributory factor in what happened to MM. IMO
He had the chance to be in there with them - for a time. I think that he knew they were there and it wasn't by chance that he came across them. The group of parents and the locations were too visible for this not to have been noted.
Where it's contradictory, based on what we know of his past crimes; is it likely that he would have carried out an attack knowing that the parents could come back?
He presumably planned the attack on the American woman. I'm assuming she lived alone, or had he been watching her movements - visitors etc over a period of time?
The biggest puzzle is trying to put a profile together of CB and his past crimes to fit this one. IMO
I believe his past crimes, burglaries and rape rape were organised and would have taken a certain amount of planning.
Like DLk and others I'm theorising that the burglary of 5A was CB's original intention, if anything it was 'work' to him so I guess a little planning goes into all our work days.
But after entering the apartment and after seeing MM, his impulsive, uncontrolled sexual traits towards children overrode his initial 'planned' burglary.
Not all crimes and psychological profiles fit into a neat little box, We do know CB displayed impulsive behavior (the playground incidents)
OR he woke MM as he entered 5A to burgle, tried to silence her, resulting in death, then took her body to conceal evidence. No abuse may have even taken place.
Also those with ASPD tend to see no danger and have trouble in automatic detection and responsivity to threat so it's entirely possible, in that moment, he didn't even care whether he got caught in the apartment.
JMO
This is from earlier in June.
"German police have not ruled out a sexual motive for the alleged crime against Madeleine, which is being treated as murder by the BKA.
Christian Hoppe of the BKA added that the suspect may have broken into an apartment in the Ocean Club complex in Praia da Luz - where Madeleine was on holiday with her parents, Kate and Gerry McCann, and her twin siblings Sean and Amelie - before
spontaneously kidnapping her."
'We think Madeleine McCann is dead', say German prosecutors, as suspect named