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

"Kicker [cost]" means "You may pay an additional [cost] as you cast this spell."

If the copied creature has in its mana cost, X is 0.

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

If the copied creature is copying something else, then the tokens enter the battlefield as whatever that creature copied.

If the copied creature is a token, the tokens created copy the original characteristics of that token as stated by the effect that created that token.