Conspire represents both an additional cost and a triggered ability that triggers when you cast the spell if you paid that cost.

Each creature you tap for conspire must share a color with Rally the Galadhrim For example, you could tap two green creatures, two blue creatures, or one of each. For either or both of the creatures, you may tap a multicolored creature that's green and/or blue, and possibly other colors as well.

The triggered ability that creates the copy can itself be countered by anything that can counter a triggered ability. If it is countered, no copies will be put onto the stack.

The copy that conspire creates is created on the stack, so it's not "cast." Abilities that trigger when a player casts a spell won't trigger.

A copy of a spell can be countered like any other spell, but it must be countered individually. Countering a spell with conspire won't affect the copy, and vice versa.

If a spell with conspire has targets, you may choose new targets for the copy.

The token copies exactly what was printed on the original creature and nothing else (unless that creature is copying something else or is a token; see below). It doesn'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 has {X} in its mana cost, X is 0.

If the copied creature is a token, the token that's created copies the original characteristics of that token as stated by the effect that created that token.

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

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 copied creature will also work.