So what kind of an abductor would take the time to wipe prints off toyshelves, books, mirrors and dressers? It makes no sense to me. It's not like they'd be touching all of those things. Opening and closing the window all the time, you'd have prints on them.
AND, it would be completely normal for Mom and Dad's fingerprints to be on the window, as maybe a little girl that age might not be able to push up the window herself.