You obviously think that they were tracking Madeleine's scent but realistically would an abductor carrying a child really think it a good escape plan to loop back through the main resort? If that was the case, they would have been better going out of the patio door.....which I assume you believe that they entered through? Also, even if Madeleine was on foot, most children in my experience would have grabbed the soft toy or blanket for comfort, and at the very least would have been calling out or crying whilst walking down a pretty dark path - yet the scent makes it all the way to the Tapas car park without anyone hearing or seeing anything. In my humble opinion, both the open shutters and the dog scent trail make the idea of two abductors more likely, but again I can't be sure as we don't know for sure who the dogs were tracking.
But many believed 'Tannerman' was MM's abductor so you could just as easily ask would an abductor carrying a child really think it a good escape plan to cross a t-junction close to where T9 were staying hence JT made the observation? If Tannerman was MM's abductor, I don't believe he was, I would have thought he would have been better walking away in the opposite direction?
I would assume MM was sleeping when she was abducted in much the same way the children seen with Tannerman and Smithman were.
Search and Rescue dogs are used all over the world in all sorts of situations and there's no evidence to suggest they're unreliable. The items handed to the GNR officers to enable the dogs to sniff MM's scent had been in close proximity to MM's body. Even if you believe KM wanted to mislead then whose scent were the dogs tracking? If the twins, KM or GM they would have followed a different trail.