Well, I for one would never use new footage of anyone who wasn't the original actor unless it was a long shot. It would be easier to add a CG tear to Carrie Fisher's face. I will examine the feasibility of all those things, both on the Death Star and on Alderaan, but most of them will just not be possible.

I might loop in new dialogue and do some snipping and actually not have Alderaan destroyed at all. I'll let them destroy Dantooine instead :-) Yay, Alderaan survives.

Anyway, all this is really asking too much of the original material. If we had raw footage to choose our own takes, you'd have completely different versions of Star Wars already, but we don't. We're really limited to and by the material available.

What I definitely can do is the expanded destruction of Alderaan, and I'm pretty certain we can tease out enough to give Leia some thoughts in her cell as the Death Star approaches. I'm not sure I want to change too much, otherwise we go too far down the road of unpicking the original.