Offensive Espeon isn't viable at all because it's outclassed by other offensive Psychic Pokemon such as Speed Deoxys,
[email protected], Alakazam and other special attackers in general. Yes, Magic Bounce makes Espeon immune to status moves, but its frailty lets it down in that regard; this also makes it very prone to priority. Aegislash also laughs at what your Espeon can do, even HP Fire. At this point, you're better off using Speed Deoxys, who can get hazards up fast or act as a revenge killer with even better coverage:
-Psycho Boost
-Superpower
-Ice Beam
-Knock Off/Stealth Rock
Nature: Naive
EVs: 20 Atk/252 SAtk/236 Spe
Item: Life Orb
or
-Reflect
-Light Screen
-Taunt
-Stealth Rock/Magic Coat
Nature: Timid
EVs: 252 HP/4 Def/252 Spe
Item: Light Clay
or
-Stealth Rock
-Spikes
-Taunt
-Magic Coat/Superpower
Nature: Timid/Jolly
EVs: 252 HP/4 Def/252 Spe
Item: Focus Sash
If you insist on keeping Espeon, this is the best it can do for the team:
-Reflect
-Light Screen
-Psychic/Psyshock/Yawn
-Baton Pass
Nature: Timid
EVs: 252 HP/4 Def/252 Spe
Item: Light Clay
Ability: Magic Bounce
Swampert faces plenty of competition with other bulky Water Pokemon, such as Wash Rotom, Gastrodon and Quagsire.
Wash Rotom:
-Volt Switch
-Hydro Pump
-Will-o-Wisp
-Pain Split/Rest
Nature: Bold
EVs: 248 HP/216 Def/44 Spe
Item: Leftovers/Chesto Berry
or
-Volt Switch
-Hydro Pump
-Thunderbolt/Hidden Power (Ice)
-Will-o-Wisp
Nature: Modest
EVs: 228 HP/60 SAtk/220 Spe
Item: Leftovers
or
-Volt Switch
-Hydro Pump
-Hidden Power (Ice)/Thunderbolt
-Trick
Nature: Timid/Modest
EVs: 4 HP/252 SAtk/252 Spe
Item: Choice Scarf
Gastrodon:
-Earthquake/Earth Power
-Scald
-Ice Beam/Toxic
-Recover
Nature: Relaxed
EVs: 248 HP/252 Def/8 SDef
Item: Leftovers
Ability: Storm Drain
Quagsire:
-Earthquake
-Scald
-Toxic
-Recover
Nature: Relaxed
EVs: 252 HP/252 Def/4 SDef
Item: Leftovers
Ability: Unaware
I don't think Xatu should be on the team at all. Sure, having a backup Magic Bounce user is nice, but it takes a lot of prediction to know when the opponent will status you. Xatu is still weak to Stealth Rock if it was laid down before it switched in. Having actual Rapid Spin/Defog support is better should Espeon go down:
Starmie:
-Hydro Pump/Surf
-Thunderbolt/Psyshock
-Ice Beam
-Rapid Spin
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Leftovers/Life Orb
Ability: Natural Cure
or
-Scald
-Rapid Spin
-Psyshock/Ice Beam/Thunderbolt
-Recover
Nature: Timid
EVs: 248 HP/32 Def/4 SAtk/224 Spe
Item: Leftovers
Ability: Natural Cure
Excadrill:
-Earthquake
-Rock Slide/Iron Head
-Rapid Spin
-Swords Dance/Stealth Rock
Nature: Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Leftovers/Air Balloon/Chople Berry
Ability: Mold Breaker
or
-Earthquake
-Iron Head
-Rock Slide
-Rapid Spin
Nature: Adamant/Jolly
EVs: 120 HP/136 Atk/252 SDef (Adamant) or 252 Atk/4 Def/252 Spe (Jolly)
Item: Assault Vest (Adamant)/Choice Scarf (Jolly)
Ability: Mold Breaker
Mandibuzz:
-Foul Play
-Roost
-Defog
-Toxic/Whirlwind/Knock Off
Nature: Bold/Impish
EVs: 248 HP/252 Def/8 SDef
Item: Leftovers
Ability: Overcoat
Crobat:
-Brave Bird
-Defog
-Roost
-Taunt/Toxic
Nature: Jolly
EVs: 168 HP/136 Atk/4 SDef/200 Spe
Item: Black Sludge
Ability: Infiltrator
Tentacruel:
-Scald
-Sludge Bomb
-Rapid Spin
-Toxic/Knock Off
Nature: Bold
EVs: 252 HP/224 Def/32 Spe
Item: Black Sludge
Ability: Liquid Ooze
Mega Blastoise:
-Water Pulse/Scald/Hydro Pump
-Dark Pulse
-Aura Sphere/Ice Beam
-Rapid Spin
Nature: Modest
EVs: 252 HP/252 SAtk/4 SDef
Item: Blastoisinite
Conkeldurr should use 252 Atk/4 Def/252 SDef as its EV spread, as its Special Defense is significantly lower than its HP. This way, Assault Vest can boost Conkeldurr's low Special Defense to even higher levels.
I don't like having Articuno on an OU team. While Freeze-Dry is a good move, it was given to Pokemon who simply don't have what it takes in OU. Articuno's terrible defensive typing makes it go down to common attacks such as Stone Edge and Bullet Punch. Find something else to replace it. While Volcarona is 4x weak to Stealth Rock as well; it has the raw stats and setup move to be effective in OU. Both Tornadus forms and Moltres are also better Hurricane abusers:
Volcarona:
-Quiver Dance
-Fire Blast/Fiery Dance
-Bug Buzz
-Hurricane/Giga Drain/Psychic/Hidden Power (Ground)
Nature: Timid/Modest
EVs: 252 SAtk/4 SDef/252 Spe
Item: Life Orb/Lum Berry
Ability: Flame Body
Incarnate Tornadus:
-Rain Dance
-Hurricane
-Superpower/Focus Blast
-Taunt/Knock Off
Nature: Naive/Timid
EVs: 4 Atk/252 SAtk/252 Spe
Item: Damp Rock
Ability: Prankster
Therian Tornadus:
-Hurricane/Air Slash
-U-turn
-Knock Off
-Superpower/Focus Blast
Nature: Naive
EVs: 4 Atk/252 SAtk/252 Spe
Item: Life Orb
Moltres:
-Fire Blast
-Hurricane
-Hidden Power (Fighting/Ground)
-U-turn/Roost
Nature: Timid/Modest
EVs: 4 Def/252 SAtk/252 Spe
Item: Life Orb/Choice Specs