If you Knock Out a Pokemon using one of Tyranitar GX's attacks, do you get to take a prize card if the Pokemon is sent to the Lost Zone due to Tyranitar GX's "Lost Out" Ability?
Yes, you do. It is still Knocked Out.
Source:
Lost Thunder FAQ (2018-10-20), TPCi Rules Team (2018-11-01)
Does using Trumbeak's "Mountain Pass" Ability count as playing it from the hand? If so, would it be blocked if my opponent used Chimecho's "Bell of Silence" attack on the previous turn?
No, it is not being played from the hand. You are revealing the Trumbeak and then putting it into the Lost Zone; that is not blocked by Bell of Silence.
What happens if you use Rayquaza GX's "Stormy Winds" Ability, but can only discard less than 3 cards from your deck? Do you get to attach a basic Energy card from your discard pile to Rayquaza GX or not?
If you can discard at least 1 card from your deck, you can use the Ability and attach a Basic Energy card from your discard pile. If you can't discard any cards, you can't use it.
Source:
TPCi Rules Team (2018-08-16), TPCi Rules Team (2018-09-06)
If Voltorb is attacked by Blastoise EX's "Rapid Spin" which pushes it to the Bench after doing damage, do you still flip for Voltorb's "Destiny Burst" Ability or not?
Yes. Destiny Burst checks for two things: Voltorb was damaged by an attack while it was your Active Pokemon, and Voltorb was Knocked Out by that attack. So even though you don't check for a KO until the attack is completed, the criteria for using Destiny Burst has been met, so it can be used. This holds true for any similar Ability that triggers when the Pokemon is Active and gets damaged by an attack.
Source:
XY FAQ (2014-02-06), TPCi Rules Team (2014-02-06), TPCi Rules Team (2018-08-09)
Does Venusaur's "Jungle Totem" Ability boost the damage output of Rayquaza GX's "Dragon Break" attack since "each Basic {G} Energy attached to your Pokemon provides {G}{G} Energy"?
Yes, just because the Basic Energy card is now providing two units of energy doesn't change the fact that it's still Basic Energy.
Say I have Slaking with "Lazy" as my Active Pokemon and my opponent has Wobbuffet with "Bide Barricade" as their Active Pokemon; also my opponent has Garbodor on the Bench and currently "Garbotoxin" is disabling all other Abilities. If I play Field Blower to discard the Pokemon Tool from Garbodor so "Garbotoxin" is no longer in effect, does my "Lazy" or my opponent's "Bide Barricade" go into effect first?
In this scenario Lazy activates first. If Abilities activate at the same time, Abilities of the player whose turn it is activate first; therefore, Slaking's Ability activates first, since it's the player with Slaking's turn.
Can Marshadow GX's "Shadow Hunt" Ability allow you to attack on your first turn using Pheromosa GX's "Fast Raid" attack if Pheromosa GX is in the Discard Pile?
Yes, it can because going first is part of the Fast Raid attack that is being copied.
What happens if both Slaking with "Lazy" and Garbodor with "Garbotoxin" in play? Do they cancel each other out or what?
It depends on the order in which each Ability gets activated. Both Lazy & Garbotoxin require a condition in order to activate (either being the Active Pokemon or having a Tool attached), so when one of the abilities is active the other one is prevented. But if the ability gets disabled (like if Slaking is no longer the Active Pokemon or if Garbodor loses its attached Tool), then the other ability can activate even if it was previously prevented.
Source:
Celestial Storm FAQ (2018-07-20), TPCi Rules Team (2018-08-02)