I have a couple issues to settle with what's being discussed here'bouts. Maybe someone can set me right.
Why does Qui Gon have to disappear to set up his reappearance? He learned how to commune with the living from "the other side." He didn't know how when he died. He didn't prepare for it the way that Ben and Yoda did. And if he disappears in the funeral pyre, then people have to react to it (unless everyone disappears during their funerals -- and if that's the case, what's the point?) THat will add one more very heavy element into an already crowded scene. The actual missing part of that scene is the grief that Anakin should be feeling. Rather than listening to Mace and Yoda, we should have a close-up of Anakin where we can see the burning confusion in his eyes. He's been torn from his mother by a father figure who's burning right before his eyes - is this all that Anakin hoped it would be? I bet not.
So I recommend Qui Gon simply burn away as shown-- unless CC can straighten me out.
Second, I point out that when these Jedi disappear, they leave behind their cloaks and blankets. They disappear in only part of their garments -- leaving something behind. I don't think seeing Darth Vader's costume disappear from his funeral pyre will work. Anakin is inside that thing -- he won't need the costume where he's going and he isn't wearing it when we see him. If Vader is to disappear, I suggest it has to happen on the Death Star when Luke has removed his mask. He should somehow disappear from inside the costume, leaving Luke with an empty shell.
Don't know exactly how to do it. Aftereffects? Photoshop? Wishful Thinking?