Really? So glib. Just because the parents are in the Tapas? The children could all be together in one apartment with the baby monitor being used. They could all be together in one apartment with a baby-sitter. They could all be in their own apartments with between one and four baby-sitters caring for them. One of the group could be baby-sitting (Sun Matt, Tues Russ, Wed Rachael were all absent). They could be in the night cheche.
Please identify the viewpoints in those four blocks which would enable someone to watch the front and back doors of 5A from 5.30 to 8.30?
SO you don't think it would have been possible for a would be abductor to figure out that the children were left in their own apartments? What babysitters? Were there any in evidence seen entering apartments?
But perhaps you're right. Perhaps they chanced it, Apartment 5a being the easiest to access, nothing ventured, nothing gained, they got lucky, Madeleine didn't. Who knows? Intruders have entered apartments that were known to contain parents, after all....
As for your other question - no idea. Ask the resident expert.