I don't really care know the zako's names, except maybe the "head zako", maybe she's like second in command, but she's still nonetheless, another minion. For example, in the movie Double Take (2006), during the shootout outside a government building, there is two leaders of the squad of zako, but they are dressed the same as the other henchwomen. Eventually, all the zako are shot, and so is one of the head zako, who just becomes another dead minion in a sea of dead minions. The army fighters who took them out don't even give notice to her, or any of the other gals, and head on to the government building.
I also believe the zako should be evil, or poor minded. But as far as when they're killed, they should most likely deserve it, especially if they're also using firearms or something else to kill the heroes. If they are KO'd, like in a kung-fu style fight, it can feel less serious, because they were not killed. Even better (if there aren't an "endless" supply of them) is if they are KO'd during a fight, then at a later scene, are killed. I like when there is, say, only 8-10 zako, and we see them throughout a film, and you can identify each one on their looks, and then during a finale fight or shootout, can follow each one as they are eventually taken out.
Sorry, went off on a thread there for a sec. Another example of a time when I wouldn't mind observing a zako's personality, is if, for example, a spy is having a drink at a bar or night club, and two women, zako's dressed in evening wear approach him, they flirt, and they eventually leave and go somewhere else, maybe another hot spot, or maybe a hotel room. During which, we get an idea of the girls personalities, as they interact with the spy. They start both putting the moves on the spy, and he goes for it at first, getting to at least second base with them, when suddenly one of them pulls out a knife and tries to stab the spy. He blocks her, pushes her away, and knocks the other girl away, and pulls out his gun. He also takes the knife, and tells the girls something funny, like "nice try" or something. He then leaves.
Later on in the movie, we would see those 2 zako girls in the ranks of the other zako, dressed identically to everyone else. They would eventually get beaten up/killed by the spy in a final battle, and the spy wouldn't even give a second glance to them, along with the bevy of other henchwomen.
Otherwise, I don't really want any glimpse of a zako's personality aside from her responding to the leader's orders or informing one of her comrades of a situation, all in serious tone.