Possibly but in order not to wake her, she could have been picked up from her bed with her head on the right arm and passed in that same position to someone at the other side of the window.
Sorry Anthro, but I doubt that would be possible, given the limited space between the under window bed and the chair. IMO, the possible lifter would be unbalanced just standing there, one foot in front of the other, without the added weight of Madeleine pulling him over, when leaning forward and slightly sideways.
Also the window is very narrow to pass Madeleine through without her touching either side and leaving traces IMHO
I am happy to be found wrong on this, if someone would like to set up an exact replica situation
I think that s/he had to be carried out via the front door. A very safe thing to do given the recessed almost pitch black porchway - and no-body passed by that doorway. It was like being at the end of a cul de sac, no one went past unless visiting 5A