Advice needed for my team

Okay, I decided to form a Pokemon team around my three favorites and a strategy I've been working on. Here's what the finished team will look like:

Aegislash
Ghost/Steel
Ability: Stance Change
Item: Leftovers
Moves
Crobat
Poison/Flying
Ability: ???
Item: Black Sludge
Moves
Crustle
Bug/Rock
Ability: Sturdy
Item: ???
Moves
Forretress
Bug/Steel
Ability: Sturdy
Item: ???
Moves
Greninja
Water/Dark
Ability: Protean
Item: ???
Moves
As you can see, I haven't quite settled on who gets what items. I also need to pick a mega-evolver and sweeper. Either Charazard (with Charazite X) or a Blaziken. And could there be Pokemon better fitting my team?

Thunder Flare said:

Okay, I decided to form a Pokemon team around my three favorites and a strategy I've been working on. Here's what the finished team will look like:

Aegislash
Ghost/Steel
Ability: Stance Change
Item: Leftovers
Moves

King's Shield
Toxic
Shadow Claw
Sacred Sword
​

Crobat
Poison/Flying
Ability: ???
Item: Black Sludge
Moves

Zen Headbutt
Confuse Ray
Fly
Poison Fang
​

Crustle
Bug/Rock
Ability: Sturdy
Item: ???
Moves

Sand Tomb
Stealth Rock
Sand Attack
Rock Wrecker
​

Forretress
Bug/Steel
Ability: Sturdy
Item: ???
Moves

Spikes
Toxic
Stealth Rock
Gyro Ball
​

Greninja
Water/Dark
Ability: Protean
Item: ???
Moves

Water Shuriken
Night Slash
Dig
Aerial Ace
​

As you can see, I haven't quite settled on who gets what items. I also need to pick a mega-evolver and sweeper. Either Charazard (with Charazite X) or a Blaziken. And could there be Pokemon better fitting my team?

Click to expand...

First of all, get rid of Toxic on Aegislash and put Shadow sneak in there. King's sheild+Shadow sneak is a common and good combo.
Next up, Put Rapid Spin on Forretress, as quickly as you can.
Then,you need 2 pokemon who can cover spore spammers so i suggest either Mega-Houndoom or Mega-Charizard X for the added dragon type.
Last but not least, you want something that can tank Fairies better that poison types and i would suggest Klefki OR Steelix.
And you don't need Crustle if you have Forretress...

So your team should be like that:

Aegislash
Ghost/Steel
Ability: Stance Change
Item: Leftovers
Moves
Crobat
Poison/Flying
Ability: ???
Item: Black Sludge
Moves
Forretress
Bug/Steel
Ability: Sturdy
Item: ???
Moves
Greninja
Water/Dark
Ability: Protean
Item: ???
Moves

Charizard
Ability: Blaze
Item: CharizarditeX
-Flare Blitz
-Dragon Claw
-Heat Wave
-Air Slash

Klefki
Ability: Magician
Item: (leave empty so magician can do its thing)
-Play Rough
-Heal Block
-Crafty Sheild (for spore spammers\Toxic spammers)
-Psychic

EVs and natures would be nice here, btw.

Infiltrator is Crobat's best ability, but it may or may not be hard for you to get becaues its a Hidden ability.

Klefki should use Prankster instead of Magician. Priority status is a nice thing to have.

Physical Greninja sounds plausible, but doesn't work when put to actual use. So a special set:

-Greninja w/Life Orb
Nature: Hasty/Timid
Ability: Protean
EVs: 252 Sp.Attack, 252 Speed, 4 HP
Moves: Hydro Pump/Surf, Ice Beam, Dark Pulse, Grass Knot

KillerCroCohen said:

First of all, get rid of Toxic on Aegislash and put Shadow sneak in there. King's sheild+Shadow sneak is a common and good combo.
Next up, Put Rapid Spin on Forretress, as quickly as you can.
Then,you need 2 pokemon who can cover spore spammers so i suggest either Mega-Houndoom or Mega-Charizard X for the added dragon type.
Last but not least, you want something that can tank Fairies better that poison types and i would suggest Klefki OR Steelix.
And you don't need Crustle if you have Forretress...

So your team should be like that:

Aegislash
Ghost/Steel
Ability: Stance Change
Item: Leftovers
Moves

King's Shield
Shadow Sneak
Shadow Claw
Sacred Sword
​

Crobat
Poison/Flying
Ability: ???
Item: Black Sludge
Moves

Zen Headbutt
Confuse Ray
Fly
Poison Fang
​

Forretress
Bug/Steel
Ability: Sturdy
Item: ???
Moves

Rapid Spin
Toxic
Stealth Rock
Gyro Ball
​

Greninja
Water/Dark
Ability: Protean
Item: ???
Moves

Water Shuriken
Night Slash
Dig
Aerial Ace
​

Charizard
Ability: Blaze
Item: CharizarditeX
-Flare Blitz
-Dragon Claw
-Heat Wave
-Air Slash

Klefki
Ability: Magician
Item: (leave empty so magician can do its thing)
-Play Rough
-Heal Block
-Crafty Sheild (for spore spammers\Toxic spammers)
-Psychic

Click to expand...

I don't agree with these set suggestions. Even though King's Shield sets are easily played around, they're viable nonetheless. Aegislash can also be played as a wallbreaker/offensive pivot:
-Shadow Ball
-Iron Head/Shadow Sneak
-Sacred Sword/Shadow Sneak
-King's Shield
Nature: Quiet
EVs: 240 HP/252 SAtk/4 SDef/12 Spe
Item: Leftovers

or
-Shadow Ball
-Shadow Sneak
-Sacred Sword
-Iron Head/King's Shield
Nature: Quiet
EVs: 252 Atk/252 SAtk/4 SDef
Item: Leftovers/Life Orb

or
-Swords Dance
-King's Shield/Shadow Claw
-Shadow Sneak
-Sacred Sword
Nature: Adamant
EVs: 240 HP/252 Atk/4 SDef/12 Spe
Item: Leftovers

or
-Swords Dance
-Autotomize
-Shadow Claw
-Sacred Sword
Nature: Adamant
EVs: 84 HP/252 Atk/4 SDef/168 Spe
Item: Leftovers

or
-Autotomize
-Shadow Ball
-Hidden Power (Ice)
-Sacred Sword/Iron Head/Flash Cannon
Nature: Rash/Modest
EVs: 88 Atk/252 SAtk/168 Spe
Item: Life Orb/Weakness Policy

Crobat is best played as an offensive stallbreaker/Defogger. Its offensive move pool is shallow and doesn't have good coverage together. Brave Bird is its only viable offensive option:
-Brave Bird
-Defog (clears away entry hazards and screens on both sides of the field)
-Roost
-Taunt/Toxic
Nature: Jolly
EVs: 168 HP/136 Atk/4 SDef/200 Spe
Item: Black Sludge
Ability: Infiltrator

Forretress is massive setup bait. While it may be a subpar option this generation for this reason alone, people still use it for the Rapid Spin and hazard support it provides:
-Stealth Rock/Spikes
-Rapid Spin
-Gyro Ball
-Earthquake/Volt Switch
Nature: Relaxed
EVs: 252 HP/252 Def/4 SDef
Item: Leftovers

Charizard X is supposed to use physical attacks only because of Tough Claws powering up its contact moves (which tend to be physical in nature). Leave special moves to Charizard Y:
-Dragon Dance
-Flare Blitz
-Dragon Claw
-Earthquake/Roost
Nature: Adamant/Jolly
EVs: 252 Atk/4 Def/252 Spe
Item: Charizardite X
Ability: Blaze

or
-Fire Punch
-Dragon Claw
-Will-o-Wisp
-Roost
Nature: Jolly
EVs: 248 HP/84 SDef/176 Spe
Item: Charizardite X
Ability: Blaze

Time and time again, I've always disapproved of physical Greninja. Its Attack isn't high enough to make the most out of its move pool, and its special moves hit harder:
-Hydro Pump/Surf
-Ice Beam/Dark Pulse
-Extrasensory/Dark Pulse
-U-turn/Hidden Power (Fire)
Nature: Hasty/Timid
EVs: 4 Atk/252 SAtk/252 Spe
Item: Life Orb
Ability: Protean

or
-Spikes
-Hydro Pump/Surf
-Ice Beam
-U-turn/Extrasensory
Nature: Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Life Orb/Focus Sash

Prankster is the one and only ability Klefki should use because of its wide support move pool. Magician is absolutely useless in comparison:
-Reflect
-Light Screen
-Spikes
-Dazzling Gleam/Foul Play
Nature: Bold
EVs: 252 HP/152 Def/104 SDef
Item: Light Clay
Ability: Prankster

Oh, if you wanna use a Blaziken:

-Blaziken w/Blazikenite or Focus Sash
Nature: Adamant
Ability: Speed Boost
EVs: 252 Attack, 252 Speed, 4 Defense
Moves: Protect, Flare Blitz, High Jump Kick, Swords Dance/Shadow Claw

If you use it with a Focus Sash, either lead with it or make sure it only comes in after one of your guys gets KO'd and there's no entry hazards on the field. Regular Blaziken should probably use Swords Dance instead of Shadow Claw, while Mega Blaziken can forgo Swords Dance in favor of Shadow Claw.

General idea seems to be going for Charizard and replacing Crustle for Klefki. Sorry, Crustle, but I have to go with what will be useful for the team. Thanks for the advice everyone, and any more than can be given is welcome.