Ok your theory on scar akai is brilliant and the idea that shuu is bourbon while with good points still fall since in they implied that Julie was vermont because she was drinking sherry and had a picture map of conan ran and ai. Seeing shuu drinking bourbon either means he is bourbon or he is an ally my thought is sera is bourbon because there was a small scene where we get sera is akai's niece and if she did learn that he was a double agent but the CIA didnt want her so she entered the BO and is attacking from the inside that she can get close to conan possibly akai told her about him or she noticed that he was apart of the CIA for a time.
Thought there is not alot of theories that are in the show since well the new movie is coming out soon, but scar akai is a rouge agent he keeping tabs on the BO by following the CIA but its never elaborated on in the show now except for the reccent episode where (SPOILER) is discovered but now im off topic.
ok im bored think on what i said