timdiggerm said:

Ender, nightstalk,

While that's the obvious answer, it means you can't show Ani's death. No lava fight, no explanation for how he ended up so scarred, no nothing.

The whole thing will have to be reworked. You remove Palpatine actually naming Anakin "Darth Vader". You give the impression that Anakin dies on Mustafar. By showing the battle and having him "die" without Palpatine showing up, you can just assume Vader is the new villain of the film, in the same way that Maul and Dooku and Grievous were. You also have to cut most of the tying up stuff. I'm almost thinking you could show Yoda arriving on Dagobah, and end with Padme's funeral procession. If you add Obi-Wan to Padme's funeral, you tie up the fate of everyone you think is alive.

You could also change up Obi-Wan's line from "a young Jedi named Darth vader, who was..." to "a young jedi, who as a pupil of mine...