Re: Fett idea of him contacting Vader.

I do not see how such a thing could flow in terms of pacing and editing. Luke arrives at Jabba’s palace, comes into the throne room, confronts Jabba - and ends up in the Rancor Pit. Do you then cut to Fett contacting Vader? When he is brought out after killing the Rancor, Jabba pronounces the death sentence at the Pit of Carkoon and everyone is leaving to board the sail barge. Does Fett tell him then? How does that figure into Vader wanting him alive while Jabba sentences him to death? Is Fett gonna talk Jabba out of killing him or kidnap Skywalker for Vader? I do not see how you overcome that pacing and jarring plot issue.

It is not necessary. Fett looks to be contracted by Jabba, probably a more lucrative deal than the uncertainty of dealing with Vader and deals that get altered.

The ONLY thing I would want fixed is Fett’s demise - and it could be done as simply as re-editing the sequence after Luke cuts the gauntlet cord. After Fett gets up right after the shot of the other skiff shooting at them, have Luke’s saber being shown cutting into the backpack and sending Fett flying. Of course Ady will kill the silly shot of Fett flailing about while screaming as he flies into the sail barge. But hey - since the Beak is gone from the Sarlaac - why not make the tendrils a lot more deadly = maybe spiked ends like a venus flytrap that secure themselves to flesh? and have them wrap up Fett pretty good after he falls into the sand and drag him into the pit? That might be a more viable and realistic re-edit with some minor new shots needed from a Fett costumer and someone dressed in black like Luke who can whirl around to strike his backpack.

Less is always more sometimes.