Can I use Zoroark GX's "Trade" Ability to discard a card from my hand if there are no cards left in my deck?
Yes you can. The first part of Trade is to discard a card from your hand, period. Then you do as much of the rest of the Ability as you are able to.
Source: TPCi Rules Team (2019-03-21)
Can I use Zebstrika's "Sprint" Ability to discard my hand if there are no cards left in my deck?
No, you cannot. Discarding your hand is a cost not the effect, and you cannot use Abilities for no effect.
Source: TPCi Rules Team (2019-03-21)
Can I use Zebstrika's "Sprint" Ability if I have no cards in my hand?
Yes, since you can have a hand of zero cards you can use Sprint as long as there are cards in your deck to draw from.
Source: TPCi Rules Team (2019-03-21)
Can I use Swampert's "Power Draw" Ability to discard a card from my hand if there are no cards left in my deck?
Yes you can. The first part of Power Draw is to discard a card from your hand, period. Then you do as much of the rest of the Ability as you are able to.
Source: TPCi Rules Team (2019-03-21)
If I use Judge Whistle and choose to put a "Judge" card from my discard pile into my hand, can I put a "Judge Whistle" into my hand?
No, that choice only allows you to put a card named "Judge" into your hand; it does not allow you to get a card "with Judge in its name".
Source: Team Up FAQ (2019-01-18), TPCi Rules Team (2019-01-31)
When using Ingo & Emmet, if I choose to draw 5 cards from the bottom or my deck, what happens to the top card that I looked at?
You put it back on top before you draw the 5 cards from the bottom.
Source: Team Up FAQ (2019-01-18), TPCi Rules Team (2019-01-31)
If my opponent Knocks Out my Active Pokemon and I promote my Zapdos to be Active after the attack, do I get the bonus 70 damage for "Thunderous Assault"?
No. In this scenario you promoted the Zapdos while it was still your opponent's turn. In order to get Thunderous Assault's additional damage it would have to become Active during YOUR turn.
Source: Team Up FAQ (2019-01-18), TPCi Rules Team (2019-01-31)
When I use Zangoose's "Head Hunt" attack, do I have to put all Pokemon I find into my hand, or can I choose to discard some or all of them?
Since you get to choose which Pokemon to reveal, you can choose to discard some or all of them.
Source: Team Up FAQ (2019-01-18), TPCi Rules Team (2019-01-31)
If my opponent has no benched Pokemon, do I do 50 damage to their active Pokemon when I use Nidoking's "Drag Off" attack?
No. Damage is only done to the "new Active Pokemon". If there is no switch, then no damage is done.
Source: Team Up FAQ (2019-01-18), TPCi Rules Team (2019-01-31)
When using Hoopa GX's "Devilish Hands GX" attack, can I keep choosing a Pokemon that would already be Knocked Out by previous choices, or do I have to choose a different Pokemon once I have done enough damage to KO the first one?
You make all 6 choices before doing any damage; so if you wish, you can do more damage than you need to a Pokemon in order to knock it out.
Source: Team Up FAQ (2019-01-18), TPCi Rules Team (2019-01-31)