While it is certainly possible that Ghostwalker is using Harlequin to pull a long con on the Azzies, that honestly doesn't sound like his style.
My honest opinion? Ghostwalker's actions in DeeCee are the closest you'll ever get to seeing a Great Dragon being a fool for love, and leaping without looking at the consequences first. He was focused on healing Zebulon (shutting the Rift was just a convenient byproduct), and he really didn't care about what happened after that. But then, perhaps I'm just a romantic at heart.
Of course, now that things are in motion, he'll be putting plans in place to try and counter Harlequin and his Jester's Army. Which means that, even though he isn't running a con on them, he may still use their actions to take the Azzies down a few pegs. I'd look for Ghostwalker to try and take the offensive, starting with getting runners to disrupt this Jester's Army, and to act as go-betweens with other potential players, specifically the great dragons and immortal elves, but also the governments involved in Denver, and players in the underworld. Most directly, I'd expect him to get in contact with Amazonia and Horizon.