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.