Other known variants
x2
-30WhirlwindYour opponent switches the Defending Pokémon with 1 of his or her Benched Pokémon, if any. (Do the damage before switching the Pokémon.)
Mirror MoveIf Pidgeotto was attacked last turn, do the final result of that attack on Pidgeotto to the Defending Pokémon.
Very protective of its sprawling territory, this Pokémon will fiercely peck at any intruder.
Can you do Pidgeot EX's "Mirror Move" attack if the opponent's last attack "placed damage counters" (as opposed to "doing damage")?
No. Placing damage counters is an effect. Mirror Move does not copy any other types of effects from the last attack either.
If an opponent's attack damages my benched Pidgeot EX, can it do "Mirror Move" during my next turn and attack for the amount of damage it received while on the bench?
Yes, it can.
Let's say I have Machop active with a Focus Sash attached, and my opponent's Mewtwo-EX uses "X Ball" for 360 damage with four Double Colorless Energy and a Muscle Band attached. The Focus Sash leaves Machop with 10 HP remaining. If I then use Ninja Boy to switch Machop with Pidgeot-EX and then use its "Mirror Move" attack, does Pidgeot-EX do 360 damage in return?
Yes, it would. When using Ninja Boy the amount of damage done last turn is remembered by the new Pokemon, so Mirror Move would do 360 damage to your opponent's Active Pokemon.