Hmm considering how some characters in this show can be identified by more than one name, Hei has 3 (Hei,
Li Shun Sheng Li Sheng Shun, BK-201), November 11 has 3 (Jack Simon, November 11, Mr Smith), Chiaki has 3 (Shinoda Chiaki, Ayame, Haraguchi)... ok maybe I'm pushing it, but couldn't it just be the same person with two names?
Looking at the trend of colors...
Hei - black hair, black cloak
Yin - silver hair
Carmine - carmine hair
Amber/Bai - amber eyes, white one piece
Huang? I don't know, maybe the writer is playing with us here. His hair is brown, eyes are black, don't seem to have a favourite color in his wardrobe. Maybe it's taken from his real name, the chinese surname "Huang".
I have another speculation which might support this one person two names theory: Perhaps Hei's organisation has many teams of agents in other parts of the world. The agents use colors as their code name (why Mao is an exception I don't know) and the language of the naming indicates their team affliations.
ie.
Hei, Mao, Huang, Yin and maybe Pai (was once with the group) as one team. Carmine, Amber (before her disappearance) plus other colors could make up another team. And who knows, maybe there's a team consisting of Akai, Murasaki or Kin out there in the DtB world.