Be warned, I did kinda change movesets and items up a lot.
Sylveon - Miranda
Ability: Pixilate
Item: Pixie Plate/Choice Specs/Choice Scarf/Assault Vest
Moves: Hyper Voice, Hidden Power Ice, Light Screen, Shadow Ball/Magic Coat
Hydreigon - Cassiopeia
Ability: Levitate
Item: Assault Vest/Choice Specs/Choice Scarf
Moves: Flash Cannon, Dragon Pulse, Dark Pulse, Flamethrower/Hidden Power Fairy
Metagross - Dell
Ability: Clear Body
Item: Leftovers/Choice Band
Moves: Meteor Mash, Bullet Punch, Zen Headbutt, Earthquake/Brick Break/Rock Slide
Delphox - Almia
Ability: Magician
Item: Focus Sash/Life Orb/Choice Specs
Moves: Psychic, Fire Pledge, Psychic Terrain, Snatch/Shadow Ball/Grass Knot
Note: Snatch was specifically for dealing with Heather's Tailwind. Just having that up saved my ass so I could be sure of at least not constantly getting outsped.
Porygon2 - Hopper
Ability: Trace
Item: Eviolite
Moves: Tri Attack, Recover, two of Thunderbolt/Ice Beam/Toxic/Shadow Ball/Hidden Power Rock
Silvally - Hope
Ability: RKS System
Item: Rock Memory/Flying Memory/Dragon Memory/Ground Memory/Ground Memory/Life Orb
Moves: Multi-Attack, Ice Fang, Parting Shot, U-Turn/Rock Slide
Note: These items (although not the items of the other Pokemon on this list) are in order.