It is a tough call... one I'll need to make as well I assume. If you can stand waiting to heal to make a judgement, then likely going through surgery again along with the extra costs, you'll be more likely to get the preferred outcome.
Regarding genioplasty movement, I would think 1mm won't make much difference but 2 or more will. Generally speaking and from my research, the gonian or tip of chin bone should align vertically with your lower incisors. But I've seen exceptions either way so you must take into account soft tissue of the chin. Personally I think 3 or 4 for you now would be good but again, IDK how the bsso will affect everything.
From what I've read, even surgeons don't like to make promises based on morphs and such because the soft tissue piece is difficult to predict. Too bad you don't have more time, because a decision would best be made after input from a few different surgeons.
Edit: and after seeing your pics again, I think 3mm is plenty assuming the mandibular occlusal plane angle remains unchanged.