I would go with 0 Def and 0 SpD IVs on Marshadow because it seems clear to me that you want him to survive on sash into endeavor, so you want minimal defenses. Also, I don't know if you forgot or something but you can have 0 IVs, so 0 IVs in hP too, not 1. Also, you have 2 Megas which is literally impossible, even in AG? In addition, I think your a little bit too Endeavor happy. One S Rocks on your side and half your team is useless. I also noticed you have a lot of Fairy Types. Diance is really bulky so 0 HP + Endeavor isn't going to do much except make him effectively have mediocre 31 IV Defences, so that's not going to work. Replace Diance, for a good Defog user like defensive Pelipper or something, it doesn't really matter so long as you have a Defog User, because when people run one main sweeper, they usually run a hazard setter too, like Ferrothorn or Smeargle or something, plus you need to keep your sash Marshadow to stay relevant, so I strongly recommend one. Mixed Rayquaza-Mega, isn't very viable; I would suggest a more standard D Dance set: Roost, Dragon Dance, Dragon Claw, Dragon Ascent. Also, 2 megas, like I said earlier, isn't allowed, so get rid of Altaria-Mega for an Unaware Wall like Clefable or Quagsire. Also, sash Xerneas is highly unorthadox and is terrible in every way, so I would go for a Power Herb + Geomancy, Moonblast, Psyshock, and HP Fire. Other than that, nothing really troubles me too much about your AG team, so I hope you take my recommendations into consideration, and that your team does well in AG.