At origins I was lucky to be at a table run by Henry and he said many people in the known lands refer to the Green Moon as Paradice of the Gods and/or the place They came from before pursuing the Other. That was news to me! So I'm passing it n to the forum.

I had inferred that before about the equation of the Green Moon with the Paradise of the Gods. I don't recall whether it was spelled out or was entirely my inference, but my extensive notes do indicate that Viridis represents the verdant Paradise of the Gods.

One big clue to me was that in the eloran story from the Gods' War of the search for Belissarda and the Other, the Elemental Lords asked if the Gods of Men had checked the Green Moon yet, and they replied, “He is not there. We . . . have already looked there.” [Codex Arcanis, 2nd ed., p. 177]

Getting confirmation from Henry is definitely a boon!

I vaguely recall in one of the Legends of Arcanis Hard Points, the PCs may have had a fleeting visit to the Green Moon. It was one of those time-warp occurrences that Henry threw into the story.
When in the timeline was hazy (past/future/alternate reality).

To my knowledge we have never been to either moon. There was a vision post-Storm of robed individuals on the black moon. And in the mod where the PCs were sent into the future we saw the black moon explode.