First, I will give you my opinions on the sets (I know you didn't make them, but why not).
Decidueye is better off with Leftovers, since you can't have two Pokemon with an LO, plus it heals Substitute damage.
OK. This is an... interesting Emboar set. It doesn't have Rest, but it has Sleep Talk... and a Choice Scarf with Sleep Talk, for that matter. What happens when Emboar is your last Pokemon and you wake up? Personally, I would swap Sleep Talk for Earthquake, an essential move for almost every physical attacker that learns it.
Poisonium Z for Salazzle, but other than that, nice set.
I would use Nasty Plot/Focus Blast/Flamethrower/Dark Pulse on Zoroark. Since it has Timid, I feel like Sucker Punch isn't super good on it, especially when it has a good coverage option in Flamethrower and a good set up move in Nasty Plot. Use a Focus Sash.
As for Trevenant, I found a set very similar, but with 4 Atk, Wood Hammer, and Protect. I would keep the EV spread, but consider using Wood Hammer over Phantom Force and Protect over Substitute. Here is the set.
Haxorus looks good, maybe try a Lum Berry for Outrage/burns, but a LO is also good.
So, what Pokemon would I choose? First, I wouldn't use a physical attacker, they're generally riskier to use than special attackers (confusion, burns, and Foul Play), plus Haxorus is a physical attacker anyway. It would be nice if Salazzle had HP Ice, admittedly, so it could hit Dragon types.
Anyway, I would say Salazzle. it 4x resists Fairy, plus it can hit Steel types that are immune to/take neutral damage from Earthquake. STAB Acid Downpour at +2 will KO most Fairies for Haxorus, just in case you don't feel comfortable keeping Haxorus in to use Poison Jab on a Fairy. It can also KO Ice types with Fire Blast, another weakness of Haxorus's. Haxorus also resists Water for Salazzle.
Hope this helps! :)
