I mean...just because a Sim has an Asian-sounding name or a Middle-Eastern name doesn't really mean that they have to be that ethnicity, or even match it. They're only names after all, and even though fulleditmode-ing them all so you can change their names is a pain, it can be done. I have a friend whose family is Mexican, she doesn't have a Mexican last name nor does she look Mexican. Still is though! It's all just a weird name not matching the face thing.
And on the "what kind of city is San Myshuno" topic, does it really matter? All of the other neighbourhoods in the game (at least in my experience) usually get white generated townies, so is it really a problem to have this one that doesn't? You could just...move. Or fulleditmode them if you don't like how they're generated. Everything in the Sims is fictional so I don't think we can try to pinpoint exactly where these places would be if this was the real world.