I don't know. I've been trying to configure conjectures where the pull up is on and the daytime pants are over them. I thought maybe in her mind L was misbehaving and she told him he's getting a pull up on ready for bed and then getting his supper and going straight to bed afterwards? And maybe that would explain the pull up with the daytime clothes.
If she's angry with him (which in no way implies his fault, it implies her anger issues) then that might push her into putting the pull up on herself rather than "it's time for bed, go get your pj's on and don't forget to put on a pull up" and stick your head around the door to make sure he is doing okay? Or you could pull down the pj's a bit to make sure the pull up is on?
I'm getting a bit of a 'she has to do everything" vibe, as part of her anger management issues, because he is technically, for an average child, old enough to put on his own pull up.
But it could go back to 're-dressing' (post mortem dressing). If she is already working out that she's going to wait until the afternoon to report L getting out of the house, or being abducted from the home/garden, then she might want to put him in day clothes to further that impression.
This isn't really too important right now, because the focus is to *Find Lucas*.
On the note of finding him...if there are security cameras on homes in the street, surely LE have viewed those images to look for her vehicle pulling in and out over the previous few days? Once they see which direction she's headed and at what time, then they can pull up traffic or security camera images for the next place and try to follow her routes in that manner? It would be time-consuming, but even if she left her phone at home this would surely be a way to track her movements? And if there are places in the journey where she's taken too long to go from point D to point E, then they can get boots on the ground and visibly look for any potential hiding places that might have caught her eye in that location. If they can see her vehicle never leaves for more than an hour at a time, then that gives them about a ten- to twenty-mile radius.
The thing about serial killers...I don't think it's doable here as we only have a single point of reference, and the calculations would rely on having more than one point of reference...I believe the calculation is also about finding where the perp lives and where they might strike, not about hiding bodies? I do wish we could have a similar thing here, but I think it has to be more about psychological profiling than about pure numbers and math :-(