The team looks really good! Some things could be changed in my eyes, though. I'll bold changes and explain why.
Conkeldurr @ Assault Vest
Ability: Guts ->Iron fist
EVs: 252 Atk / 236 SpA ->236 SDef / 20 Spe
Adamant Nature
- Drain Punch
- Mach Punch
- Ice Punch
- Poison Jab ->Knock off
Iron fist is a much better ability for Conkeldurr, taking advantage over every punching move it has. Guts can be good but is mostly good in some situations while Iron fist is active all the time. It is a HA so it might be hard to get but its really worth it.
You meant 236 SDef, I hope.
Even though Poison jab is a really great move and helps against fairy's, I think that Knock off is a better move for Conkeldurr. It can knock off an item and completely screw up for an opponent.
Rotom-Wash @ Sitrus Berry ->Leftovers
Ability: Levitate
EVs: 248 HP / 252 Def / 8 SpD -> 252 HP/ 168 Def/ 88 Spd
Bold Nature
- Hydro Pump
- Volt Switch
- Will-O-Wisp
- Protect -> Pain split
Sitrus berry is very good for healing a large amount of HP quickly but Leftovers is better in the long run. Together with Pain split, you can heal off an even larger amount of HP on one round. Protect is awesome but my personal choice would be Pain split.
Ferrothorn @ Rocky Helmet
Ability: Iron Barbs
EVs: 252 HP / 88 Def / 168 SpD
Relaxed Nature
- Stealth Rock
- Toxic
- Gyro Ball
- Power Whip /Leech seed
Nothing to really say on this one. You could switch Power whip for Leech seed for some awesome stalling/recovery.
Excadrill @ Leftovers
Ability: Mold Breaker
EVs: 252 Atk / 4 Def / 252 Spe
Adamant Nature
- Drill Run
- Iron Head
- Rock Slide
- Rapid Spin
I suggest this set:
Excadrill @ Air Balloon
Ability: Mold breaker
EVs: 252 Atk / 4 Def / 252 Spe
Adamant Nature (+Atk, -SAtk)
- Earthquake
- Rock Slide
- Rapid Spin
- Swords Dance / X-scissor / Brick break
Air balloon is an awesome item for Excadrill, making it immune to ground-type moves until hit. Rock slide is self-explanatory but you should have EQ instead of Drill run. EQ is such an awesome move! SD is for eventual damage dealing but it could be switched for Iron head, X-scissor or Brick break.
Talonflame @ Sharp Beak
Ability: Gale Wings
EVs: 120 HP / 252 Atk / 136 Spe -> 192 HP / 252 Atk / 4 Def / 60 Spd
Jolly Nature
- Swords Dance
- Brave Bird
- Flare Blitz
- Roost
Talonflame is a terrifying wall breaker. Due to Gale Wings Talonflame can run Adamant and bulk. The EVs look random but actually serve a purpose. 252 Attack maximizes the damage you can do. 60 Speed outruns Excadrill so you can Flare Blitz it. 192 HP reaches an odd HP number so Stealth Rocks do slightly less damage while the last point is dumped in Defense to tank Bullet Punches a little better. If Mega Pinsir Quick Attacks are beating you Talonflame can instead run 208 Speed to outrun it, Brave Birding it to death.
Pinsir @ Pinsirite
Ability: Hyper Cutter -> Aerilate
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Swords Dance
- Return
- Close Combat ->Earthquake
- Quick Attack
Not to much to say here except for the switch to EQ. Close Combat is more of an alternative to Earthquake. It does hit Rotom-W harder than Return and allow Mega Pinsir to 2HKO physically defensive Skarmory at +2, but it also leaves you badly walled by Aegislash, which is a very bad thing. Not to mention the defense drops.
I hope that I helped!