If one of my opponent's Pokemon is Knocked Out in the middle of a turn before the attack, can I take my prize(s) right away or do I have to wait until the end of the turn?
No matter when a Pokemon gets Knocked Out during a turn, the opponent takes their prize(s) as soon as all triggered effects have finished resolving. You do not wait until the end of the turn to resolve KO's and prizes.
Source: TPCi Rules Team (2018-04-05)
What happens if my opponent failed a Confusion check last turn and I try to use Sudowoodo's "Watch and Learn" attack? Would Sudowoodo take 3 damage counters?
If the Pokemon failed its attack because of Confused, an attack was not used. Sudowoodo's Watch and Learn would simply do nothing.
Source: TPCi Rules Team (2018-03-01)
The "Prism Star rule" on the card says "you can't have more than one {*} card of the same name in your deck", but can I have more than one Prism Star cards of different names in my deck?
You can have several Prism Star cards in your deck as long as they are different names, but only one copy of each. For example, you can have one Giratina {*} and one Lunala {*} and one Super Boost Energy {*}, and so on. This rule is not ignored for Limited tournaments such as Prereleases, Drafts, etc.
Source: Ultra Prism FAQ (2018-01-19), TPCi Rules Team (2018-02-01)
When searching my deck, at what point can I no longer change my mind on which cards I am choosing?
When something says to search your deck for cards you should search the deck, make your choice, and shuffle afterward. Once you begin shuffling you may not go back and change your choice unless your opponent allows you to do so.
Source: TPCi Rules Team (2017-07-06)
Can I use Umbreon-GX's "Dark Call GX" attack to discard 2 Double Colorless Energy?
Yes, you can select 1 Energy of each Double Colorless Energy to discard both of them. This applies for discarding your own Energy for an attack and for retreating as well. So if you used Hoopa-EX's "Hyperspace Fury" attack or paid its Retreat Cost of 2, discarding 2 Double Colorless Energy would be legal options.
Source: TPCi Rules Team (2017-01-26), TPCi Rules Team (2017-06-27)
Altaria has a printed weakness to Lightning, but it also has the "Clear Humming" Ability which creates an effect that gives it no weakness. What happens if it is attacked by Zebstrika with the "Zap Zone" Ability which makes its attack's damage ignore effects on the defending Pokemon? When Zebstrika attacks Altaria, is the damage altered by weakness or not?
Zap Zone refers to "any effects on your opponent's Active Pokemon", but the term "any effects" does not include effects that alter Weakness or Resistance. So in this case Zebstrika's attack will NOT be increased for Weakness, due to Clear Humming.
Source: TPCi Rules Team (2016-03-24), TPCi Rules Changes Announcement (2017-05-03), TPCi Rules Changes Announcement (2017-05-18)
The Burned special condition has changed from Sun & Moon and onward. Now when a Pokemon is Burned in between turns you first put two damage counters on that Pokemon then flip to see if the Burned condition is removed (heads) or if it remains (tails).
Source: Sun & Moon FAQ (2017-02-02), TPCi Rules Team (2017-02-02)
If my Confused Pokemon tries to use a GX attack and flips Tails, does that use up my "one GX attack per game"?
No, if you flip tails the attack fails and you don't use up your GX attack.
Source: TPCi Rules Team (2017-01-26)
If my Zebstrika with the "Zap Zone" Ability attacks a Pokemon with {L} Weakness, does the Weakness get ignored because of "Zap Zone"?
No, Weakness & Resistance are game mechanics, they are not effects that would be ignored because of Zap Zone.
Source: BREAKpoint FAQ (2016-01-23), TPCi Rules Team (2016-02-11)