Lin using the Norinco Type 82-2 as his main weapon is very sensible, especially when he operates as an assassin dressed up like a woman. The blade can be folded inward, making it more compact to be stored in a woman's handbag. And since he's assuming a female look, it would be hard for the public and police to pin a woman to be an assassin, which Lin uses in order to be Hidden in Plain Sight.
The blade is also of Chinese origin, much like Lin himself.
Yusuke Harada having a Glock 17 pistol. Since Japanese anti-firearms laws are among the strictest in the Asia-Pacific region, he only had to rely on his corrupt father since he's the mayor of Hakata and has connection with various organized crime groups.
Enokida is not only familiar with hacking and computer, but he's also familiar with current events and news that's happening out of Japan. It makes sense since 1.) He's an informant, so he needs to stay on top of things and 2.) He "used" to be from a rich family, so his father would have sent him to a reputable school.
