What about those who are not incarnated and in the light during this period of preparation for the ascension? Will their karmic backlog be healed as well?

There will be opportunities in the future, even in the new paradigm in higher dimensions, for karmic repair work to be done and will be part of the new configuration, to allow the means for repair and realignment to still proceed. So all who choose to ascend will be enabled to do so in one way or another. It is to everyone’s advantage to do all the healing they can now, still in the physical realm they are a part of, because the healing will be more profound, more thorough, and easier to accomplish because the current energetics are a perfect match to the repair needed, and it will be more complicated to do later on from higher dimensions. But those in the light will do just fine if they miss out spending time on Earth during this healing interval.