All of the above were just added to my normal shape, which is a tad anime. Ethnically speaking, i guess i would say the Issigonis Makoto skin is fairly stereotypical Japanese - I don't wear this often because the creases are a tad odd on my shape (they look fine on the provided shape, however). L'Oeuf strays in to Vietnamese territory for me, and D-Skin is probably the most stereotypical asian/caucasoid mix, imo.
As for the no-crease issue, some Asians have it, some don't. It's largely a genetic difference. It does seem to me the farther north you go, the fewer creased eyelids you'll find. It has to do with muscular differences and fat ratios in different parts of the face. There tends to be quite a push culturally speaking towards having the crease, as it allows the eye to appear more open, and one can look more alert. As a kid, I was encouraged to stick tape on my eyelid to fix the one side that didn't crease properly (and still doesn't).
//Edit to say: i hadn't been to Issigonis for a while. they actually have quite a few asian skins here with varying (but very asian) features.