If I've already played a Supporter this turn and use Sylveon's "Wink Wink" attack, can I still use the effect of a Supporter I discard from my opponent's hand?
Yes. You are not playing a second supporter, but using its effect via an attack.
Source: Forbidden Light FAQ (2018-04-20), TPCi Rules Team (2018-05-03)
If I use Sylveon's "Wink Wink" attack and discard my opponent's Diantha, can I get 2 cards from my discard pile even it 1 of my {Y} Pokemon was not Knocked Out on my Opponent's last turn?
No, you still have to meet the requirements of the card's text. You can discard the Diantha, though.
Source: Forbidden Light FAQ (2018-04-20), TPCi Rules Team (2018-05-03)
If I use "Untamed Punch" with an undamaged Pangoro, does it still get the Confusion effect?
No, damage counters on your attacking Pangoro are required for both the Confusion and the extra damage.
Source: Forbidden Light FAQ (2018-04-20), TPCi Rules Team (2018-05-03)
If I use Aegislash's "Ticking Knock Out" attack but my opponent moves the Defending Pokemon to the bench, on my next turn if I bring that Pokemon active and damage it or if I damage it on the bench is it knocked out?
Only if you do enough damage to meet or exceed that Pokemon's remaining HP. The effect of "Ticking Knock Out" is on the Defending Pokemon and is cleared when it moves to the bench, so you would have to knock it out by normal means rather than by simply doing any amount of damage to it.
Source: Forbidden Light FAQ (2018-04-20), TPCi Rules Team (2018-05-03)
The wording of Exeggcute's "Multiply" attack is a little ambiguous. Does it mean you can only search for one Exeggcute, or as many Exeggcute as you want?
Just one.
Source: Forbidden Light FAQ (2018-04-20), TPCi Rules Team (2018-05-03)
If I use Greninja GX's "Haze Slash" attack to shuffle it back into my deck and also Knock Out the Defending Pokemon, who promotes a new Active Pokemon first?
In this case you promote first. Greninja GX is shuffled back in as an effect of the attack before KO's are checked, so it must be replaced before either player checks for KO's.
Source: Forbidden Light FAQ (2018-04-20), TPCi Rules Team (2018-05-03)
Does Araquanid's "Bubble Trap" attack get its bonus damage if the Pokemon that used "Bubble" on my previous turn was Knocked Out or is no longer in play?
Yes, you get the bonus damage. The effect of "using Bubble" is on the player, not on the Pokemon.
Source: Forbidden Light FAQ (2018-04-20), TPCi Rules Team (2018-05-03)
Can I play Eneporter to try and fail to move a Special Energy onto a Pyroar that is protected by its "Unnerve" Ability, or would I not be able to play Eneporter at all?
The fact that its effect will be blocked by another effect such as Unnerve does not prevent an Item or Supporter card from being played. For example, your opponent may play Eneporter to try moving a Special Energy and Pyroar is a valid target, but Unnerve blocks the effect even though Eneporter was played. Playing a card for no effect happens when the game state itself prevents any effect from taking place and in that case the card would not be played, but that is not what this example is referring to.
Source: Forbidden Light FAQ (2018-04-20), TPCi Rules Team (2018-05-03)
Does Goomy's "Sticky Membrane" Ability increase the attack cost of no energy attacks like Alolan Marowak's "Limbo Limbo" attack?
Yes, it does.
Source: Forbidden Light FAQ (2018-04-20), TPCi Rules Team (2018-05-03)
Does Goomy's "Sticky Membrane" Ability increase the attack cost of attacks where the cost is ignored, such as when "Roto Motor" applies?
No, it does not.
Source: Forbidden Light FAQ (2018-04-20), TPCi Rules Team (2018-05-03)