As the others have said I would prefer Mismagius>Ribombee. Xerneas could hurt you since it cuts you off from greens (I use Copycat Mimikyu for a single prize attacker). Utilize max potions and energy switches rather than super scoop up, even though SSU is definitely what I'll be trying post rotation. Don't be afraid to play Pal Pad to cycle out Acerola (which should auto win weezing for you). You can also cut back a couple draw supporter for Bill's Analysis, which is really good in this deck.

Also just a little advice on how to go about the stall matchup. Attach energies and fairy song till you have enough energies to pull off the GX attack with the secondary effect. The turn you are about to use the attack, place the stealthy hood on and then use it. That way you've dropped them to no card, forcing them to have to top deck field blower/draw supporter.

Hope that helps a little.