Regarding the green on the snakes Lyric1's colour photo was the main reference, although all the B&W photos from this squadron show a similar shade of grey to the OD as well. Since this squadron was based in India I went with RAF Dark Green for the colour, as that paint would likely have been more readily available locally than say USAAF Medium Green.
Lyric1 also found me colour photos of some of this squadron's later P-38Ls, one of which I previously skinned on the old shape. These did not have the snake art but their NMF was camouflaged using RAF Dark Green above and RAF Sky below. So this makes RAF dark green even more likely as the snake colour. I think it also explains the white dotted outlines to the snakes, if the green colour was more of a contrast to the OD these would not be needed.
BTW I never trust decal sheets, warbirds and profiles for this sort of thing as a lot of the people who make them tend to be lazy and just copy each other's work rather than checking original photos. So just because there are half a dozen secondary sources all saying the same thing, it does not mean it is correct. Interpreting the actual WW2 photos is the only way to go and is a lot more satisfying when you spot something no one else has. For example none of the profiles or models noticed the black and white squadron markings on the lower vertical tails. They are in shadow on the photos so you have to look really closely to see them, but they are much clearer in photos of other 459th P-38s.