Conan didn't know James from before at the time. But now, he has known Akai. Wouldn't you find it strange how Conan and Ran never seem to find Amuro familiar, at least in his actions or the way he thought ?
Quote me a dialogue where Akemi or Jodie or anyone commented Akai being a "gentleman" or something similar (make sure it's manga canon and the translation is reliable). They found him lovely, but they never stated that it was because he looks like a gentleman or so.
And you seem to be confused between "being good" and "being a gentleman". (The term "gentleman" does not really mean "a gentle man"). Good people, there are many. But NOT every good characters are with the "gentleman" type. Furthermore, an evil person or a criminal can still be a gentleman, sometimes in an even higher degree than the good guys (most obvious example would be Kaitou Kid), but most importantly, they DON'T GIVE PEOPLE THE KILLER VIBE.
Again, being good doesn't automatically make a guy "gentleman" or similar. Also, Akai's creepy look is not just temporary in one certain scene/case, it's throughout the whole series.
By the way, remember that Gosho has also done the opposite way, which is, drawing a seemingly kind/innocent character (who turns out to be evil later). This case, it may match Amuro's profile.
Still doesn't make him a "gentleman" or something similar.
To keep an eye, he could have just simply worked at Poirot, and observe the Mouri family, that would be much safer if he already knew that there's a BO member hanging around. Why bother doing something so openly like becoming Kogoro's apprentice and appearing with him everywhere ? It will only draw more attention, someone who's as smart as Akai will never do something that reckless. Also, Amuro KNEW that Conan was missing the other day, but didn't speak it up early, which showed the lack of care. Had it been Akai instead, would he have acted like that ?
The revelation still has to make sense. Shocking, but still has to be logical. So far there are still many holes with this theory.
Speaking of logical, you never answered me, how exactly did Akai changed into "the Amuro form" ? And the handedness ??? If someone among them was Akai, then it would most likely be Okiya.