If I use Gengar's "Hurl into Darkness" attack, can I put a LEGEND Pokemon card (the top or bottom half) in the Lost Zone?
Yes, you can. Each half of a LEGEND Pokemon is treated as 1 Pokemon card.
Source: Triumphant FAQ (2010-11-04), PUI Rules Team (2010-11-04)
If I use Gengar's "Cursed Drop" attack, can I put damage counters on more than one of my opponent's Pokemon, or do I have to put all four counters on one Pokemon?
You can put the 4 damage counters on their Pokemon in any way that you like.
Source: Triumphant FAQ (2010-11-04), PUI Rules Team (2010-11-04)
Can Mew's "Lost Link" Poke-BODY use the attack of one half of a LEGEND Pokemon if its card is in the Lost Zone? Or what if both halves of the LEGEND Pokemon are in the Lost Zone?
No, you cannot. If a LEGEND Pokemon's cards are not in play, you cannot reference its attacks, Poke-POWER, Poke-BODY, etc.
Source: Triumphant FAQ (2010-11-04), PUI Rules Team (2010-11-04)
If my Active Pokemon does an attack that Knocks Out an opponent's Pokemon, but also switches my Active Pokemon to the Bench, would the Knocked Out Pokemon go to the Lost Zone if I bring up Gengar with the "Castastrophe" Poke-BODY?
Yes. Gengar is active at the end of the attack when Knock Out conditions are evaluated.
Source: Triumphant FAQ (2010-11-04), PUI Rules Team (2010-11-04)
If I use an attack that Knocks Out a defending Gengar with the "Castastrophe" Poke-BODY, but it also knocks itself out, does the attacking Pokemon go to the Lost Zone, or is "Catastrophe" no longer in effect when Gengar is KO'd?
Since both Pokemon are KO'd at the same time, Gengar's Catastrophe Poke-BODY is still working at the point when Knock Outs are evaluated. So the attacking Pokemon would go to the Lost Zone.
Source: Triumphant FAQ (2010-11-04), PUI Rules Team (2010-11-04)
If an opponent's evolved Pokemon is Knocked Out while Gengar is Active, does the "Catastrophe" Poke-BODY put all of the evolution stage cards and Basic Pokemon card in the Lost Zone, or just the highest stage Evolution card?
The evolved Pokemon and any of its pre-evolved stages and Lv.X cards go to the Lost Zone, and all attached Energy, Tools, etc. go to the Discard Pile.
Source: Triumphant FAQ (2010-11-04), PUI Rules Team (2010-11-04)
What happens if I attach a Rainbow Energy to Roserade with the "Energy Signal" Poke-POWER? Do I get to use both effects?
If the Energy card you attached provides all types (for example, Rainbow Energy), then both effects would trigger. Energy Signal would both Confuse and Poison the Defending Pokemon.
Source: PUI Rules Team (2010-09-30)
On the part of Legend Box where it talks about "you can play only 1 Pokemon LEGEND in this way", is that just for the play of the card, or for the entire game?
It only lasts for as long as the Trainer is being used. It just means that if you reveal two or more complete Pokemon LEGENDs that you can only put one of them onto your bench for that trainer card played.
Source: PUI Rules Team (2010-09-23)
When using "Flower Shop Lady", do I have to put all 3 Pokemon and all 3 Basic Energy cards into my deck, or can I choose to return only 1 or 2 (or none) of each?
You must return all three of each if you are able to (or as many as you can if you have less than three). The card does not say "up to 3".
Source: Undaunted FAQ (2010-09-09), PUI Rules Team (2010-09-09)
Can I use Energy Exchanger to trade a Basic Energy for a Special Energy card?
Yes, the Trainer does not restrict its effect to only Basic Energy cards.
Source: Undaunted FAQ (2010-09-09), PUI Rules Team (2010-09-09)