Anyone get the green one? Is it a bright green or more muted than the picture?

Its a really nice rich medium green color, not muted at all.

Can the vest be detached from the jacket?

No. Metal snaps on the vest but it’s sewn into the jacket

If these are made in China, are the sizes based on the Asian size chart?

I recommend buying one or two sizes larger, if you belong to the muscle type, you really need to buy a little larger.

Does the vest unbutton?

There is no "vest" it is a faux vest. Yes it does un-button but it is all just part of the actual coat. That being said... it is cool as hell and glad I got one. I will most likely buy more in different colors.