Any enters-the-battlefield abilities of the copied permanent will trigger when the tokens enter the battlefield. Any "As [this permanent] enters the battlefield" or "[This permanent] enters the battlefield with" abilities of the copied permanent will also work.

If the copied permanent had in its mana cost, X is 0.

The tokens copy exactly what was printed on the permanent and nothing else (unless that permanent was copying something else or was a token; see below). They don't copy whether that permanent was tapped or untapped, whether it had any counters on it or Auras and/or Equipment attached to it, or any non-copy effects that changed its power, toughness, types, color, and so on.

If the copied permanent is a token, the tokens created by Fractured Identity copy the original characteristics of that token as stated by the effect that put it onto the battlefield.

If the copied permanent was copying something else, the tokens enter the battlefield as whatever that permanent was copying.

If the exiled permanent was a commander, the tokens won't be commanders.