Can I use both Victini's "Victory Star" Ability and Glimwood Tangle stadium to reflip coins from an attack twice?
No, you cannot. You can use either the ability or the stadium, but not both of them. As a general rule, you can't use more than one reflip effect at a time.
Source: TPCi Rules Team (2020-09-24)
If my already-poisoned Pokemon is hit by Dragalge's "Poison Cultivation" attack then I use Switch while Dust Island is in play, is my new Active Pokemon poisoned with a regular condition (only one damage counter in between turns) or with the effect from "Poison Cultivation" (ten damage counters in between turns)?
If the Poison effect places more than one damage counter during the Pokémon Checkup phase between turns, then switching the Pokémon out using a Trainer card while Dust Island is in play will retain the modified Poison effect of placing multiple damage counters on the new Active Pokémon.
Source: TPCi Rules Team (2020-09-24)
How does Billowing Smoke work with Greedy Dice or Jirachi {*} and its "Wish Upon a Star" Ability?
If you KO a Pokemon with Billowing Smoke attached, you do not get to use Greedy Dice nor Wish Upon a Star since neither of those cards would be going into your hand. Any Prize cards that would be taken for a Pokemon that has Billowing Smoke attached are discarded, not taken.
Source: Darkness Ablaze FAQ (2020-07-31), TPCi Rules Team (2020-08-13)
What happens if I play Bird Keeper but there aren't any Pokemon on my bench?
If you only have one Pokemon in play, you cannot play Bird Keeper.
Source: Darkness Ablaze FAQ (2020-07-31), TPCi Rules Team (2020-08-13)
Can you use Pokemon Breeder's Nurturing to evolve Pokemon if Dracovich's "Primal Law" Ability is active?
Yes, you can still use Pokemon Breeder's Nurturing since the Pokemon is coming from the deck and not from your hand.
Source: Darkness Ablaze FAQ (2020-07-31), TPCi Rules Team (2020-08-13)
If I use Steenee's "Captivate" attack while Spikemuth stadium is in play, does the opponent put any damage counters on their Pokemon?
No, Captivate would not trigger Spikemuth since it was not moved during the opponent's turn.
Source: Darkness Ablaze FAQ (2020-07-31), TPCi Rules Team (2020-08-13)
If I have Eternatus VMAX with "Eternal Zone" Ability in play and I use Devolution Spray Z to devolve one of my benched Darkness type Pokemon to a non-Darkness type Pokemon with enough damage already on the devolved Pokemon to knock it out, is it KO'd before having to reduce my Bench down to 5 Pokemon, or if I discard it to reduce my bench is it not KO'd?
You would discard your Bench down to 5 first, then check for a KO. That means you could discard the newly devolved Pokemon to avoid a KO, even if Eternatus VMAX is the one being devolved!
Source: TPCi Rules Team (2020-08-13)
Lysandre and Boss's Orders cannot be included in the same deck. This is similar to the rule that says Professor Juniper, Professor Sycamore, and Professor's Research cannot be included in the same deck.
Source: TPCi Announcement (2020-04-16), TPCi Rules Team (2020-04-30)
What happens if Cinderace V with the "Field Runner" Ability is in play while Galar Mine is also in play?
Cinderace V would have no Retreat Cost. When effects that increase something like Retreat Cost by a particular amount are stacked on top of effects that make something like Retreat Cost vanish, the vanishing effect takes priority.
Source: Rebel Clash FAQ (2020-04-18), TPCi Rules Team (2020-04-30)