As an abduction is a possibility I have no problem with a theory suggesting how it could have been accomplished.
This one does seem a little over complicated. As a 'planned abduction it is also extremely inefficient. We have a lookout who can't see the most important parts of the street. We have two involved in the actual abduction solely for the purpose of explaining an open window and shutters as far as I can see. We have the lookout communicating by lighting his/her lighter which involves the perps keeping their eyes glued to a balcony while trying to do the job. The lookout is on a public balcony where he could be challenged by a passing resident or a smoker like him. Next we have him moving through the block and exiting out of a garden gate but I don't know if the public could do that. Finally he is scared off because there are people around, when all he had to do was drive up the road, round the corner and pick up the carrier. Miles away in minutes. Good planners would have changed vehicles very quickly anyway, so even if his number was taken it wouldn't have mattered. Not that I can think of a reason why anyone would have taken it.
No moving cars were reported by those in the street, whatever the direction taken. No open window, curtains or shutters were noticed by the 9.30pm checker. A pile of cigarette butts were reported to be on the balcony by a person who shouldn't have been on the balcony himself imo. He seems to be the only person who was offered alternative accommodation while waiting for his flight home although he was on the same flight as everyone else. If the cigarette butts were left by the watcher his lighter must have been flickering like mad; very confusing for the perps.
Try turning it round for a moment and start trying to make it happen. Smooth off the rough edges.
Communication. Not by a mobile phone, surely. It doesn't make sense it was by mobile phone, does it? Voice and text messages are out. Put it on vibrate and the only thing you know is ... someone, somewhere is calling.
Therefore communication is likely to be by other means. Here's an idea that does not appear anywhere so far in the files. It is pure speculation, a hypothetical to get secure simple communication, within Sadie's theory.
The perps went to one of the local Chinese bazaars and bought two very cheap and cheerful signalling devices. Commonly called LASERS.
One was red. which meant stop, hide, or scarper. One was green, which means it was clear to go.
A communication system that is safer than mobile phones, dirt cheap, and practicably undetectable.
I am not saying it happened this way. I have no evidence to support that it happened this way. But it is going to be tough on anyone who claims to be sure it did not.