I put in some time today with TFA, and have put together a few mockup clips to see what it would take to move the destruction of Hosnian Prime to right after Han’s death.
https://vimeo.com/164864645
For the first scene with Snoke, we would remove Hux, and begin the scene once he’s exited the room. I think it’d be okay to leave the SKB establishing shot, though. A small amount of FX work would need to be done to paint Hux out of a few frames as he finishes walking out of frame.
https://vimeo.com/164864663
Next, we will need to remove Hux’s speech and move it to later. This means we will follow Rey as she runs from Maz’s basement, and continue following her until she notices the TIEs coming in for attack. One problem with moving the destruction of Hosnian Prime to later means that Finn left with the space pirates, and yet later appears back with Han and Maz. The best solution I can think of is to do some audio and visual FX work to make it look like he is reacting to the incoming TIEs, and merely imply that he returned in order to help fight.
https://vimeo.com/164864669
After the interrogation of Rey, we see Snoke again. Here, we will need to bake in parts of Hux’s conversation with Snoke that we removed from earlier. I’ve noted in the clip a few shots that will require FX work to show Kylo Ren unmasked.
https://vimeo.com/164864713
After Ren throws a fit upon finding Rey’s empty cell, we can insert the Hux speech. Once it cuts to people working at control stations, we seamlessly segue into the sun being sucked up, which was originally at this point in the film anyway.
During the Resistance briefing, remove Leia announcing that they are the next target.
Also, remove Threepio’s line in a subsequent base scene, “It would take a miracle to save us now.”
https://vimeo.com/164864963
And here is the destruction of Hosnian Prime, Starkiller Base’s sole target. I flipped one shot of the beam vertically so that it tracked better.
One would also need to remove the short scene right after Rey and Finn run from the building where we are told the weapon will fire in two minutes.
I’m still not entirely sure this goal can be achieved seamlessly, but I hope so. Good luck to anyone trying to make this work.