If I attack with Sceptile's "Power Poison" attack, do I have to discard an Energy card if I don't want to Poison the opponent's Pokemon?
It is not optional. Even if the damage would be enough to Knock Out the Pokemon, you still have to discard an Energy and Poison it.
Source: Primal Clash FAQ (2015-02-05), TPCi Rules Team (2015-02-05)
Does Sharpedo EX's "Hunt" attack do 30 damage if the opponent cannot switch their Active Pokemon to the Bench or if the Bench is empty?
If you cannot switch the opponent's Pokemon there is no "new Active Pokemon" to be damaged, so no damage is done.
Source: TPCi Rules Team (2015-02-05)
For Milotic's "Aqua Swirl" attack who gets to choose which Benched Pokemon becomes the new Active Pokemon?
First off, since the attack says "you may" the attacking player gets to choose if any switching happens at all. Then if so, the opponent gets to choose which the Benched Pokemon becomes their new Active Pokemon.
Source: Primal Clash FAQ (2015-02-05), TPCi Rules Team (2015-02-05)
What happens if Mew EX uses its "Versatile" ability to copy Xerneas EX's "X Blast" attack? Can it use "X Blast" again the following turn or not?
When Mew EX attacks, Versatile uses the attack name specified. So when it attacks with X Blast, Mew EX cannot use that attack twice in a row.
Source: TPCi Rules Team (2015-02-05)
Can I attach a Team Flare "Pokemon Tool F" card to my opponent's Pokemon-EX if it has the "Omega Barrier" Ancient Trait?
Yes, you can. The text of Omega Barrier says its effect excludes Pokemon Tools and Stadium cards.
Source: Primal Clash FAQ (2015-02-05), TPCi Rules Team (2015-02-05)
If I use Escape Rope but my opponent's Active Pokemon has the "Omega Barrier" Ancient Trait does he or she have to switch it? Or if they have a Pokemon with "Omega Barrier" on the bench can he or she choose that and not switch it to Active?
If your opponent has an Active Pokemon with "Omega Barrier", then Escape Rope's effect will be blocked. If a Pokemon with "Omega Barrier" is on the bench, choosing that Pokemon will not stop the effect as the Active was the target of Escape Rope.
Source: Primal Clash FAQ (2015-02-05), TPCi Rules Team (2015-02-05)
What happens for Omega Barrage if the Pokemon is Confused?
You need to flip for Confusion twice if you choose to attack twice. One flip for the first attack, then flip again if you decide to attack again.
Source: TPCi Rules Team (2015-02-05)
If I only have one energy card attached to Excadrill, can I use its "Omega Barrage" to attack with "Dredge" first to attach two energy cards, then attack a second time with "Mach Claw"?
Yes, that would work.
Source: Primal Clash FAQ (2015-02-05), TPCi Rules Team (2015-02-05)
If I attack using a Pokemon that has the "Omega Barrage" Ancient Trait, can I do things like attach an Energy or play a Trainer between attacks?
No, you would resolve all effects from the first attack and then either perform your second attack or pass. You don't get to go back into the main part of your turn again.
Source: Primal Clash FAQ (2015-02-05), TPCi Rules Team (2015-02-05)
If I use Sceptile's "Nurture and Heal" ability, is that an extra Energy card attachment or does it count as my one attachment for the turn?
It is an extra Energy attachment. You still get to attach one other Energy card as your normal attachment for the turn.
Source: Primal Clash FAQ (2015-02-05), TPCi Rules Team (2015-02-05)