Death

Let's just say Marcellus got medieval on his ass.

I heard he moved out to the suburbs and settled down.
He and the gimp adopted some nice African boys and are teaching them wrong from right.
He's an active member of the PTA and coaches little league. A pillar of the community.

he obviously called in some hard hitting, pipe laying mother#$#@'s.. I assume Zed was tortured in some inhuman way, and then eventually left to die

Haha, I was watching the 2011 interviews from the BD and Samuel L Jackson's mother apparently asked him "why'd they put that movie together all wrong?"

I realise that, hence the tongue in cheek remark about time travel. The British film magazine
Empire
actually published an article putting the film in chronological order and yes, according to that, Butch and Fabienne tearing off on the chopper would be the last scene in
Pulp Fiction
.
"Chicken soup - with a beep straw."

The cleanup after Jules and Vincent's accident takes place quite some time before the Butch/Marsellus incident. Butch and Fabienne riding off on the bike is the final scene in the film's chronology.

Based on the original script the Wolf got involved. No wonder Raquel does not see him very much. He probably still had the pliers in his pocket when he went round to resolve the dilemma of Jules and Vincent Except that this would entail time travel
"Chicken soup - with a beep straw."

No, they used the blowtorch to heat up the pliers, creating a red hot pincer, a medieval torture device used to rip out chunks of flesh. Hence, "I'ma get medieval on your ass."

At the risk of sounding graphic, I'm going to presume that they tore out each tooth of his with the pliers and used the blowtorch to cauterize the wounds so he doesn't bleed to death, prolonging his torture. God knows what else they did with him, but that's up to the viewer's imagination.
"Wasn't Einstein German?"
"Hard to tell from his accent, Russ."

But not before Marsellus got medieval on his ass. A pair of pliers was mentioned. So was a blowtorch.
"Chicken soup - with a beep straw."

Zed's dead baby, Zed's dead

Lol, too funny.

Zed's fate?
Well, his father spent a fortune reconstructing the damage done to his lap rocket area, but the side effect is his skin turned a fluorescent yellow.

One of these days I'm going to cut you into little pieces.

Did you watch the movie FruitCake? Which part did you not understand?