Monotype Ghost Team Help

[Charcoal Embers]

Alright. I'm not great at making a very good team. If you see my battles, you know how I am with making teams. My favorite type is ghost though. So here is the monotype ghost team. Critique is very much wanted.

Jellicent (F) @ Rocky Helmet
Ability: Cursed Body
EVs: 252 HP / 144 Def / 4 SpA / 108 SpD
Calm Nature
- Recover
- Scald
- Hex
- Dazzling Gleam

Cofagrigus (M) @ Sitrus Berry
Ability: Mummy
EVs: 252 HP / 76 Def / 80 SpA / 100 SpD
Relaxed Nature
IVs: 0 Spe
- Hex
- Will-O-Wisp
- Trick Room
- Pain Split

Dusknoir (F) @ Assault Vest
Ability: Pressure
EVs: 252 HP / 252 Atk / 4 Def
Impish Nature
- Ice Punch
- Power-Up Punch
- Earthquake
- Shadow Sneak

Trevenant (M) @ Lum Berry
Ability: Harvest
EVs: 252 HP / 252 Atk / 4 SpD
Adamant Nature
- Rest
- Will-O-Wisp
- Horn Leech
- Leech Seed

Sableye (F) @ Sablenite
Ability: Prankster
EVs: 252 HP / 252 Def / 4 SpA
Bold Nature
- Will-O-Wisp
- Recover
- Calm Mind
- Dark Pulse

Doublade (M) @ Eviolite
Ability: No Guard
EVs: 252 HP / 128 Atk / 128 SpD
Careful Nature
- Swords Dance
- Shadow Sneak
- Sacred Sword
- Iron Head

 

[PlatinumDude]

Other than hitting Dragons, Dazzling Gleam isn't doing much for Jellicent. The threat of Scald burns is generally enough to deter most physical Dragons from switching in. Jellicent's physical bulk isn't that good, really, meaning that it can't really make use of Rocky Helmet; that item is better suited for physically bulky Pokemon. A better take on specially defensive Jellicent is this:
-Scald
-Hex/Shadow Ball/Taunt
-Will-o-Wisp
-Recover
Nature: Calm
EVs: 252 HP/212 SDef/44 Spe
Item: Leftovers
Ability: Water Absorb

Cofagrigus is doing too much at once. Trick Room sets should use an offensive set and spread to make the most out of the 5 turns. A better defensive Cofagrigus is:
-Toxic Spikes
-Shadow Ball/Hex
-Will-o-Wisp
-Pain Split/Snatch
Nature: Bold
EVs: 252 HP/252 Def/4 SDef
Item: Leftovers

This team lacks powerful attackers outside of Doublade. Dusknoir isn't one of those attackers because it lacks a good Ghost STAB. Have you even considered Gengar or Chandelure?

Gengar:
-Substitute
-Shadow Ball
-Will-o-Wisp
-Taunt/Disable/Sludge Wave/Sludge Bomb
Nature: Timid
EVs: 28 HP/148 SAtk/80 SDef/252 Spe
Item: Black Sludge

or
-Hex
-Taunt
-Will-o-Wisp
-Substitute/Sludge Bomb/Sludge Wave
Nature: Timid
EVs: 8 HP/248 SAtk/252 Spe
Item: Black Sludge

or
-Shadow Ball
-Sludge Bomb/Sludge Wave
-Focus Blast
-Taunt/Destiny Bond
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Life Orb

Chandelure:
-Fire Blast
-Shadow Ball
-Hidden Power (Fighting)/Energy Ball
-Trick/Energy Ball
Nature: Timid/Modest
EVs: 4 Def/252 SAtk/252 Spe
Item: Choice Scarf/Choice Specs
Ability: Flash Fire

or
-Shadow Ball
-Fire Blast/Will-o-Wisp
-Substitute
-Taunt
Nature: Modest
EVs: 160 HP/156 SAtk/192 Spe
Item: Leftovers
Ability: Flash Fire

Despite its offensively-leaning stats, Trevenant is better off using defensive spreads, given how it relies on defensive berries to function:
-Substitute
-Leech Seed
-Will-o-Wisp
-Phantom Force/Horn Leech
Nature: Careful
EVs: 252 HP/4 Def/252 SDef
Item: Sitrus Berry
Ability: Harvest

or
-Horn Leech/Shadow Claw
-Will-o-Wisp
-Leech Seed
-Rest
Nature: Careful
EVs: 252 HP/4 Def/252 SDef
Item: Lum Berry
Ability: Harvest

Under normal circumstances, Super Size Gourgeist now outclasses Trevenant, as it has better bulk to match its good support move pool:
-Will-o-Wisp
-Leech Seed
-Synthesis
-Seed Bomb/Shadow Sneak
Nature: Impish
EVs: 252 HP/160 Def/96 SDef
Item: Leftovers
Ability: Frisk

While it seems tempting to have Doublade use Swords Dance to break things down, it has a tendency to get itself worn down fast in the process, given its bad Speed:
-Gyro Ball
-Toxic
-Rest
-Sleep Talk/Sacred Sword/Pursuit
Nature: Sassy
EVs: 252 HP/4 Atk/252 SDef
Item: Eviolite

 

[Charcoal Embers]

So, does this mean I hit all the wrong points with this team?

Um... but yeah. I will say that the Adamant nature on Trevenat is a mistake. Careful is what I would normally use it with with the second set with Leech Seed, Horn Leech, Wil-o-wisp and Rest. And yeah, Daziling Gleam on Jileccent I already learned isn't great. I was in a battle the other day against a dragon monoteam and it didn't even KO a Hydregon. Then the weakness policy activated on it.

 

[Charcoal Embers]

Other than hitting Dragons, Dazzling Gleam isn't doing much for Jellicent. The threat of Scald burns is generally enough to deter most physical Dragons from switching in. Jellicent's physical bulk isn't that good, really, meaning that it can't really make use of Rocky Helmet; that item is better suited for physically bulky Pokemon. A better take on specially defensive Jellicent is this:
-Scald
-Hex/Shadow Ball/Taunt
-Will-o-Wisp
-Recover
Nature: Calm
EVs: 252 HP/212 SDef/44 Spe
Item: Leftovers
Ability: Water Absorb

Co***rigus is doing too much at once. Trick Room sets should use an offensive set and spread to make the most out of the 5 turns. A better defensive Co***rigus is:
-Toxic Spikes
-Shadow Ball/Hex
-Will-o-Wisp
-Pain Split/Snatch
Nature: Bold
EVs: 252 HP/252 Def/4 SDef
Item: Leftovers

This team lacks powerful attackers outside of Doublade. Dusknoir isn't one of those attackers because it lacks a good Ghost STAB. Have you even considered Gengar or Chandelure?

Gengar:
-Substitute
-Shadow Ball
-Will-o-Wisp
-Taunt/Disable/Sludge Wave/Sludge Bomb
Nature: Timid
EVs: 28 HP/148 SAtk/80 SDef/252 Spe
Item: Black Sludge

or
-Hex
-Taunt
-Will-o-Wisp
-Substitute/Sludge Bomb/Sludge Wave
Nature: Timid
EVs: 8 HP/248 SAtk/252 Spe
Item: Black Sludge

or
-Shadow Ball
-Sludge Bomb/Sludge Wave
-Focus Blast
-Taunt/Destiny Bond
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Life Orb

Chandelure:
-Fire Blast
-Shadow Ball
-Hidden Power (Fighting)/Energy Ball
-Trick/Energy Ball
Nature: Timid/Modest
EVs: 4 Def/252 SAtk/252 Spe
Item: Choice Scarf/Choice Specs
Ability: Flash Fire

or
-Shadow Ball
-Fire Blast/Will-o-Wisp
-Substitute
-Taunt
Nature: Modest
EVs: 160 HP/156 SAtk/192 Spe
Item: Leftovers
Ability: Flash Fire

Despite its offensively-leaning stats, Trevenant is better off using defensive spreads, given how it relies on defensive berries to function:
-Substitute
-Leech Seed
-Will-o-Wisp
-Phantom Force/Horn Leech
Nature: Careful
EVs: 252 HP/4 Def/252 SDef
Item: Sitrus Berry
Ability: Harvest

or
-Horn Leech/Shadow Claw
-Will-o-Wisp
-Leech Seed
-Rest
Nature: Careful
EVs: 252 HP/4 Def/252 SDef
Item: Lum Berry
Ability: Harvest

Under normal circumstances, Super Size Gourgeist now outclasses Trevenant, as it has better bulk to match its good support move pool:
-Will-o-Wisp
-Leech Seed
-Synthesis
-Seed Bomb/Shadow Sneak
Nature: Impish
EVs: 252 HP/160 Def/96 SDef
Item: Leftovers
Ability: Frisk

While it seems tempting to have Doublade use Swords Dance to break things down, it has a tendency to get itself worn down fast in the process, given its bad Speed:
-Gyro Ball
-Toxic
-Rest
-Sleep Talk/Sacred Sword/Pursuit
Nature: Sassy
EVs: 252 HP/4 Atk/252 SDef
Item: Eviolite

Oh, but that does remind me(and sorry for the double post). But on this team, I have considered replacing someone with Drifblim JUST so that I can have some Defog Support. Have any suggestions for that or how I can maybe incorporate it, or how much of a good idea that is?