Continuity mistake: When Junior comes downstairs from shaving and enters the kitchen, his face and left ear have some smears of shaving cream. Junior walks into the den in the scene that immediately follows, and the smears of shaving cream have increased under his nose and on his left ear. (00:13:40)
Revealing mistake: The semi-automatic handgun the gunman is shooting has no rearward slide movement after each shot is fired for the shell casings to eject. The gun is firing but it's not reloading, however it's firing several shots. This is just not possible. In a few other previous gun scenes like the Mikey Palmice hit Christopher is dramatizing the recoil by moving the handgun up and down and snapping it in a way that just doesn't make any sense. (00:48:50)
Continuity mistake: In all of the episodes where Carmela hosts her film club, the theater seats in the Sopranos' screening room are gold, attached with wide trays for snacks, beverages, etc. But in this episode, when Tony and A.J. move the seats outside, they are maroon, without the wide trays.
Character mistake: During an argument between Tony and Carmela, they mention her ring, given to her in earlier episode. They refer to it as an emerald. It is a sapphire.
Answer: If you're asking how the FBI, or anyone else, faked his suicide, in the show Eugene actually committed suicide and did not fake his death. If you're asking how, in real life, they were able to make it look like actor Robert Funaro was hung, it would have been no different than any other hanging stunt. A rig or brace is placed on the actor's back, under their shirt, that supports The Weight of the actor when they are "hung" (or "hanged" depending on your word preference). The noose is lightly connected to the rope, say with wax, so that should an accident or malfunction occur with the rig, the noose would break away from the rope instead of the neck bearing the actor's weight. The rest is just acting.
Bishop73