I can't add much to what you already have gotten here. Other than my WWII USN kapok is a bluish grey somewhere betweem pure Paynes' Grey and MM Panzer grey (straps a "flatter," less blue, color than the rest). My kapok is also near unused, too, I've seen them faded to about Ghost grey, and oddly enough, almost like fresh Sky Type S (which will sound slightly oxy-moronic, describing something faded to match a new color--but, hey, there it is).
Now, the period fire extinguishers I've seen are brass or a bronze color with a brass contrasting label plate/log on them. I want to remember that ont of my old damage-control manuals said that only CO2 extinguishers were to be painets red, but, it's been decades since I've had hold of one that was close to contemporary, and I may be misremembering.
Don't forget that drills like MOB, were something that occurred often, and it was not uncommon for a "left" life ring to wind up on a "right" bracket ot the like. Or for the "inside" face to be "out". So, that could be used to add some "visual interest." The hanger would be in the camo color, but the ring could be in a base color (amybe even with a hint of a "negative" spot behind it, darker or lighter, depending on the weathering.