Vaporeon, Water Absorb. Brave Nature. Item, Leftovers.
Moveset, Scald/Ice Beam/Acid Armor/Aqua Ring
Largely on HP and Special Attack.

Leafeon, Leaf Guard. Adamant Nature. Item, Lum Berry.
Moveset, Leaf Blade/Sunny Day/X-Scissor/Swords Dance
Largely on Attack, otherwise allrounder.

Sylveon, Pixilate. Bashful Nature. Item, Pixie Plate.
Moveset, Swift/Moonblast/Shadow Ball/Calm Mind.
Largely on Special Attack and Special Defense.

Flareon, Flash Fire. Lonely Nature. Item, Charcoal/Flame Plate.
Moveset, Flame Charge/Strength/Lava Plume/Flare Blitz.
Largely on Attack and Special Defense.