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

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

The tokens created by Mirrormind Crown's ability copy exactly what was printed on the equipped creature and nothing else (unless that creature is copying something else or is a token; see below). They don't copy whether that creature is tapped or untapped, whether it has any counters on it or Auras and Equipment 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 as whatever that creature copied.

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