The thing that interests me most though if I'm honest, is the sound mix for each film in lossless audio and the potential benefits of using the blu-rays to further enhance fanedits.

I'll grant that higher quality source material will certainly increase the potential of fan projects, but having the eff'd up 2004 ANH mix in lossless does no one any good at all. A higher resolution copy of absolute garbage is still absolute garbage, and unlike the image problems there's just no fixing it--it's beyond any salvaging.

I'm not the biggest fan of the '97 SE mix, since it has many unnecessary changes and rather less power than the original 70mm version, but if that was my only option for hearing any version of the movie I'd take it and be glad. It still sounds like Star Wars, unlike the '04 which isn't even remotely recognisable. And whatever even-more-remixed nonsense the Bluray comes up with will probably be even worse.