The solicits for upcoming issues say that the Indigo secrets will be revealed soon.
Yeah, that is supposed to be the next arc in the main Green Lantern title. Unfortunately, I didn't care for the Indigo Tribe when they were first introduced, the haven't grown on me yet, and it's been so long since they were introduced that I really don't care about their back story.
As far as this book is concerned, I find myself really enjoying it more than I thought I would. I liked the little hints that Larfleeze's constructs may be slightly more sentient than originally thought. The concept of all of these planets being trapped within the Orrery is definitely I intriguing. Are they actually versions of these planets from one of the alternate 51 universes or just detailed copies?