Like B3n said, and also Contrary Serperior isn't available yet (I think apart from in Japan). 2 Leaf Storms and you'd wipe out your opponent. Also, Coil on a Contrary Pokemon? It'd just lower its stats... Contrary happens with self inflected stat changes too.
Ariados
@ Focus Sash/ Black Sludge
Ab: Insomnia
Toxic Spikes
Shadow Sneak
Sucker Punch
Sludge Bomb
Might as well go for Sucker Punch, along with Shadow Sneak, due to the increased priority of both, and to deal with Psychic types. Sludge Bomb instead of Poison Jab, because of higher damage & same accuracy and Poison chance; lower PP on Sludge Bomb doesn't matter too much.
Carracosta
@ Leftovers
Ab: Solid Rock
Stealth Rock
Crunch/ Ice Beam (coverage)
Stone Edge
Aqua Tail
You can go for Ice Beam to deal with the x4 Grass weakness, or Crunch for another physical move.
Fearow
@ Sharp Beak
Ab: Sniper
Drill Run
Drill Peck
Roost
U-Turn
I'm never a fan of choice items... nor of Fearow. To be honest I would go for a Unfezant w/ Wish (bred onto a Pidove) for extra support, or Togetic w/ Wish holding Eviolite. You already have enough coverage with the other 5, last slot should be used for support.
Raichu
@ Expert Belt
Ab: Lightning Rod
Thunderbolt
Volt Switch
Hidden Power (Ice)
Focus Blast
You might want to try Pikachu w/ Light Ball instead. The Pichu line has a pretty bleak move pool... if you want a electric alternative, Zebstrika isn't bad in NU. It out speeds Raichu, has a higher attack, and has Motor Drive & Sap Sipper to choose from. Rotom-Fan has an interesting typing, but suffers from limited movepool as well.
Serperior
Ab: Overgrow
@ Big Root
Giga Drain
Coil
Leaf Blade
Dragon Tail
Might as well make good use of Giga Drain w/ Big Root.
Cinccino
@ Life Orb/ Lum Berry
Ab: Skill Link
Rest/ Bullet Seed
Tail Slap
Rock Blast
U-Turn
You can always do a Rest + Berry combo on Cinccino as well to extend its lifespan.