OD green is green with a yellow tint.
Ranger green is green with a brown tint.
Smoke green/smoke grey/mouse grey is green with a grey tint.
No sure on foliage except that it’s very light green.
Khaki is a light tan.
Coyote is a darker, browner tan.
Coyote tan and coyote brown are the same.
That’s either FDE or Coyote, at least that’s what it looks like to me.
A computer monitor isn’t the best way to tell colors. You’ve got the variables of lighting in the original photograph to contend with, then you have the issue of how your monitor renders the colors. Your best bet is to hit the closest shop to you and check some colors out. It needn’t be nylon, any chance you have to look at rail covers/ladders, stocks, grips, etc. will give you a good idea about FDE vs OD vs FG.
Foliage Green (Magpul,Tangodown, Ergo and BlueForceGear)
Norrells moly resin finish’flat desert tan’, Gunners are called ‘Coyote brown’.
OD Green (Magpul and Daniel Defense).
Magpul stock (flat dark earth), Tangodown grip (flat dark earth), Norrells moly resin finish on VTAC tube and the barrel ([i]flat desert tan, barrel is discolored a little from the heat[/i]).