I love dredging up this subject:
A while back Crush (I think) brought up the fact that according to Graves, Gaia and Trivigante are the same. They shift their aspect from one to the other. Gaia (Earth, Urth) becomes Trivigante (moon, Lune). Considering the fact that GW gives uses the word Trivigaunte quite prominently in Long Sun, it is not a long stretch to assume that he is familiar with this symbolism. I think it's one more reason to believe that Green could be Urth/Ushas and Blue Lune.
One other thing that I can't seem to fit in anywhere else: If Green is such a hellish place, why does Sinew fix a lander and send Chenille to Blue and not leave himself and take his children and village with him?
Don