Yes I would agree with that Carana. I too have had that experience thinking a noise was coming from one place when It wasn't.
It doesn't change the fact that Kate says Maddie had brought this to her attention, and the children did wake up through the night on occasion. It wouldn't be wrong for Mrs Fenn to identify the McCann children bcauase she claimed it stopped when the parents came home as she heard the patio door being opened /closed. That makes a distinct sound and it came from below , was there more than one apartment below Mrs Fenn who had children?
Yes, but whose patio doors did she hear opening and closing? The closing of a patio door is a sound same as crying is a sound. If the direction of the crying cant be definitely recognised, neither can the direction of the patio door sound be recognised.
So back to square one. Which child was crying? Had it been Madeleine crying loudly then IMO all three would havebeen crying. Same with the twins, if one crying loudly all three would have been IMO.
It seems more likely that one of the other children in the block, a solitary child, was crying.