Can I use Rotom's "Mischievous Trick" Poke-POWER when I have no cards in my deck, to put a Prize card into my deck?
No, you can't. That would be far too mischievous.



x2
-20Mischievous Trick
Once during your turn (before your attack), you may switch 1 of your face-down Prize cards with the top card of your deck. This power can't be used if Rotom is affected by a Special Condition.
Plasma ArrowChoose 1 of your opponent's Pokémon. This attack does 20 damage for each Energy attached to that Pokémon. This attack's damage isn't affected by Weakness or Resistance.
Can I use Rotom's "Mischievous Trick" Poke-POWER when I have no cards in my deck, to put a Prize card into my deck?
No, you can't. That would be far too mischievous.
When I switch a Prize card and a card from my Deck with Rotom's "Mischievous Trick" Poke-POWER, can I look at either card?
No, you cannot. Keep both cards face-down when you switch them.
When using Rotom's "Plasma Arrow" attack, I get to choose one of the opponent's Pokemon and do 20 damage for each Energy attached to it; but do I do the damage to the Defending Pokemon, or to the Pokemon I chose?
To the Pokemon that was chosen. If the damage were to be done to the Defending Pokemon, there would be a "20x" value in the damage field of the attack.