Need Suggestions for this team

Hey there. I'm not new to pokemon but I have very little competitive battle experience. I've only played competitively against a couple of friends in Gen IV but I really never had great team building or synergy. I am open to any team changes.

Sableye @ Lagging Tail
Ability: Prankster
-Trick
-Taunt
-Wil-O-Wisp
-Recover
EVs: 252 HP/120 Def/136 S.Def

Medicham @ Choice Scarf
Ability: Pure Power
-Hi Jump Kick
-Ice Punch
-Trick
-Psycho Cut
EVs: 252 Atk/252 Spe/4 HP

Metagross @ Choice Band
Ability: Clear Body
-Bullet Punch
-Meteor Mash
-Zen Headbutt
-Hammer Arm
EVs: 164 HP/252 Atk/92 Spe

Chandelure @ Life Orb
Ability: Flash Fire
-Fire Blast
-Shadow Ball
-Substitute
-Pain Split
EVs: 252 Sp. Atk/252 Spe/4 HP

Empoleon @ Choice Specs
Ability: Torment
-Hydro Pump
-Surf
-Grass Knot
-Ice Beam
EVs: 200 HP/252 Sp. Atk/56 Spe

Cloyster @ Leftovers
Ability: Skill Link
-Icicle Spear
-Spikes
-Surf
-Rapid Spin
EVs: 248 HP/84 Atk/176 Def

I was thinking of replacing Cloyster for a more reliable wall. Plus, my team could use a cut down on Ground Type weaknesses. Was thinking of replacing Cloyster and Metagross for more speed and resistance.

Medicham is mediocre in OU play because while it has great Attack courtesy of Huge Power, its average Speed lets it down. While Conkeldurr is a lot slower than Medicham, it has good enough defenses to compensate:
-Bulk Up
-Drain Punch
-Mach Punch
-Ice Punch/Payback/Stone Edge
Nature: Adamant
EVs: 120 HP/252 Atk/136 SDef
Item: Leftovers
Ability: Guts

or
-Drain Punch
-Mach Punch
-Facade/Ice Punch
-Payback
Nature: Adamant
EVs: 128 HP/252 Atk/128 SDef
Item: Flame Orb/Toxic Orb
Ability: Guts

or
-Substitute
-Focus Punch
-Mach Punch
-Stone Edge/Payback
Nature: Adamant
EVs: 252 HP/252 Atk/4 Spe
Item: Leftovers
Ability: Iron Fist

In a similar vein to Medicham, Chandelure suffers from average Speed. Gengar or Volcarona are faster alternatives:

Gengar:
-Substitute
-Shadow Ball
-Focus Blast
-Disable/Thunderbolt/Hidden Power (Fire)/Pain Split
Nature: Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Black Sludge/Life Orb

or
-Substitute/Protect
-Shadow Ball
-Focus Blast
-Hidden Power (Fire)
Nature: Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Black Sludge/Life Orb

Volcarona:
-Quiver Dance
-Fire Blast
-Bug Buzz
-Hidden Power (Rock/Ground)/Psychic
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Life Orb/Lum Berry

or
-Quiver Dance
-Fiery Dance
-Bug Buzz
-Roost
Nature: Timid
EVs: 240 HP/252 Def/16 Spe
Item: Leftovers

or
-Quiver Dance
-Fire Blast/Fiery Dance
-Bug Buzz
-Rest
Nature: Modest
EVs: 160 HP/236 SAtk/112 Spe
Item: Chesto Berry

I agree that Cloyster needs to go. Forretress makes a better Rapid Spinner, and you're in a dire need of hazards here:
-Spikes/Stealth Rock
-Rapid Spin
-Volt Switch
-Gyro Ball/Hidden Power (Ice)
Nature: Relaxed/Bold
EVs: 252 HP/252 Def/4 SDef
Item: Leftovers/Shed Shell
Ability: Sturdy

or
-Spikes
-Stealth Rock
-Gyro Ball
-Explosion
Nature: Brave
EVs: 252 Atk
Item: Custap Berry
Ability: Sturdy

Given my suggestion of Forretress, you have too many Steels. A Dragon of your own might be ideal here, such as Dragonite, Hydreigon, Lati@s or Salamence. One can go over Empoleon.