The token copies the creature as it last existed on the battlefield before it died, not as it exists in the graveyard.

If you control more than one Genestealer Patriarch as a creature with an infection counter on it dies, each one's ability will trigger, and you will make two tokens that are copies of it.

The token copies exactly what was printed on the original creature and nothing else (unless that creature is copying something else; see below). It doesn't copy whether that creature was tapped or untapped, whether it had any counters on it or Auras or Equipment attached to it, or any non-copy effects that had changed its power, toughness, types, color, or so on.

If the copied creature was copying something else, then the token enters the battlefield as whatever that creature copied.

If the copied creature had {X} in its mana cost, X is 0.

Any enters-the-battlefield abilities of the copied creature will trigger when the token enters the battlefield. Any "as [this creature] enters the battlefield" or "[this creature] enters the battlefield with" abilities of the creature will also work.