Kate's narrative is she left Madeleine holding Cuddle Cat. It puts the little girl alive at 6:00pm, and places her in bed. The mystery is how the toy got to the ledge, with no DNA present. You may well be right in your scenario; we just don't know.
What ledge? Where are you getting this info from? If the abductor lifted a sleeping MM out of bed then the abdudctor would not necessarily come into contact with CC. I thought the soc images showed CC lying mid way on MM's pillow? Children move around in their sleep any any toy companions could end up anywhere.