If my opponent used Hisuian Zoroark's "Doom Curse" attack to KO my active Great Tusk ex at the end of my next turn, would I still have to discard the top 5 cards of my deck for Great Tusk ex's "Quaking Demolition" Ability or not?
If there's an effect that KO's Great Tusk ex at the end of the turn Quaking Demolition will still trigger. All end-of-turn effects process first, then you check for any KO's afterward.
Source: TPCi Rules Team (2024-02-15)
If I use Hisuian Zoroark's "Doom Curse" attack and my opponent switches or retreats and brings up a new Active Pokemon, which of their Pokemon will be Knocked Out at the end of their next turn?
Neither! The effect of Doom Curse was on the attacked Pokemon and going to the bench removes all Attack Effects. So after the switch/retreat the Doom Curse effect is gone.
Source: Lost Origin FAQ; TPCi Rules Team (2022-09-08)