I'm trying to understand you, Namdrol la, correctly here. Correct me if I don't have this right, please. Body of light is an inner realization where nothing changes in the physical body, right?
As I understand it, yes.
One can achieve dzogchen's definition of samyaksambodhi by realization of the body of light, right?
So one would have a physical body just like before, and one would have attained the non-abiding buddhahood of kadag chenpo in this body on this Earth. Is this right?
Then, the body of great transference or the body shrinking at death, for example, is the natural dissolution of the elements into the five wisdom lights; it is at this point when one, according to the texts, looks at the lights in one's hand and maintains a form, or one doesn't do that and the form is gone. Is this right?
Well, the elements are already in the form of the five lights of wisdom even now. The only difference is that we don't perceive their actual nature. Body of light is our perception of the elements reverting to wisdom light.
Then what accounts for the omniscience?
The six abhijñās that develop naturally as one works through the four visions. The third vision corresponds with path of seeing in common mahayana.