Saheeli, the Sun's Brilliance

The token copies exactly what was printed on the original permanent, with the listed exceptions (unless that permanent is copying something else or is a token; see below). It doesn't copy whether that permanent is tapped or untapped, whether it has any counters on it or any Auras or Equipment attached to it, or any non-copy effects that have changed its types, color, power and toughness, and so on.

If the copied permanent is a token, the new token that's created copies the original characteristics of that token as stated by the effect that created the token (with the listed exceptions).

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

If the copied permanent is copying something else, then the token enters the battlefield as whatever that permanent copied (with the listed exceptions).

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