Needing help with my team

[Ezkayl]

hey, assuming this is the right place for this and the title is pretty obvious, this is a first time competitive team for me so please don't be too critical, so here it is my first 5.

Ampharos @ Ampharosite
Static || Mold Breaker
252 HP, 252 Spec Atk, 4 Spec Def - Quiet
Thunderbolt
Volt Switch
Focus Blast
Dragon Pulse

Noivern @ Choice Spec?
Frisk
252 Spec Atk, 252 Spd, 4 Def - Timid
Draco Meteor
Hurricane
Dark Pulse
Boomburst

Ferrothorn @ Rocky Helmet
Iron Barb
252 Def, 252 Spec Def, 4 Atk - Relaxed
Power Whip/Seed Bomb
Gyro Ball
Toxic
Leech Seed

Malamar @ Assault Vest
Contrary
252 Atk, 252 Spd, 4 Def
Pyscho Cut
Night Slash/Foul Play
Super Power
Rock Slide

Sylveon @ Pixie Plate
Cute Charm
252 Def, 252 Spec Atk, 4 Spd
Moon Blast
Draining Kiss
Swift
Dazzling Gleam

ok so that's what i have i'm looking for some help finding a 6th pokemon willing to take any suggestions, i have alot of offense on the team so yeah i dunno please help!

 

[PlatinumDude]

Ampharos needs enough Speed EVs to outrun Hippowdon, which can shut it down with Earthquake: 236 HP/252 SAtk/20 Spe with a Modest nature.

Dark Pulse and Boomburst don't give Noivern any noteworthy coverage. Ghost and Psychic Pokemon are already torn apart by Draco Meteor, while Boomburst is redundant with Noivern's Dragon STAB:
-Draco Meteor
-Flamethrower
-Focus Blast
-Hurricane/Switcheroo/U-turn
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Choice Specs
Ability: Frisk/Infiltrator

or
-Draco Meteor
-Flamethrower
-Focus Blast
-Dragon Pulse/Roost/U-turn
Nature: Timid/Naive
EVs: 252 SAtk/4 SDef/252 Spe
Item: Life Orb
Ability: Frisk/Infiltrator

Ferrothorn can already wear down opponents with Leech Seed, so Toxic isn't really necessary:
-Leech Seed
-Protect
-Gyro Ball/Thunder Wave
-Stealth Rock/Power Whip/Spikes
Nature: Relaxed/Impish
EVs: 248 HP/252 Def/8 SDef
Item: Leftovers
Ability: Iron Barbs

or
-Stealth Rock/Spikes
-Leech Seed
-Gyro Ball/Thunder Wave
-Power Whip/Protect
Nature: Relaxed
EVs: 248 HP/52 Def/208 SDef
Item: Leftovers
Ability: Iron Barbs

Malamar isn't really that viable, tbh, due to its lack of resistances and average stats. Conkeldurr makes a better Assault Vest user.:

Conkeldurr:
-Drain Punch
-Mach Punch
-Knock Off
-Ice Punch/Stone Edge
Nature: Adamant
EVs: 188 HP/252 Atk/48 SDef/20 Spe or 236 HP/252 Atk/20 Spe
Item: Assault Vest
Ability: Guts

You do realize that Sylveon learns much better moves apart from its Fairy STABs and the Normal moves that are affected by Pixilate, right?:
-Wish
-Protect
-Hyper Voice
-Heal Bell/Calm Mind
Nature: Bold
EVs: 252 HP/244 Def/12 Spe
Item: Leftovers
Ability: Pixilate

or
-Hyper Voice
-Shadow Ball
-Psyshock
-Hidden Power (Ground)/Baton Pass/Echoed Voice
Nature: Modest
EVs: 244 HP/252 SAtk/12 Spe
Item: Choice Specs
Ability: Pixilate

The last slot can be taken up by Rapid Spin or Defog support:

Excadrill:
-Earthquake
-Iron Head
-Rapid Spin
-Stealth Rock/Rock Slide
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Leftovers/Air Balloon
Ability: Mold Breaker

or
-Earthquake
-Iron Head
-Rock Slide
-Rapid Spin
Nature: Adamant/Jolly
EVs: 252 Atk/4 Def/252 Spe (Choice Scarf) or 120 HP/252 Atk/136 SDef (Assault Vest, Adamant only)
Item: Choice Scarf/Assault Vest
Ability: Mold Breaker

Starmie:
-Hydro Pump/Surf
-Ice Beam
-Psyshock/Thunderbolt
-Rapid Spin
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Life Orb
Ability: Natural Cure/Analytic

Mandibuzz:
-Foul Play
-Defog
-Roost
-Toxic/Whirlwind/Knock Off
Nature: Bold/Impish
EVs: 248 HP/252 Def/8 SDef
Item: Leftovers
Ability: Overcoat

 

[Puddle]

Hmm a 6th Pokemon. It looks like you need another attacker. You need someone to resist for when they try and take down the Ferrothorn. You have a couple options.

Greninja
Dark Pulse
Ice Beam
Scald
Grass Knot
Nature: +SpA/-Atk
Focus Sash/Life Orb
252Spe 252Atk 4Hp

OR

Talonflame
Brave Bird
Flare Blitz
U-Turn
Flame Charge/Aerial Ace/???
144 HP/252 Atk/112Spe
Choice Scarf/Leftovers
Nature: +Atk/-SpA

Those are just two Pokemon I like. However, I've been using this recently and it's a great water sweeper.

Crawdaunt
Aqua Jet
Crabhammer
Knock Off
Brick Break/Aerial Ace/Swords Dance
Life Orb
Adaptability
Adamant Nature
252Spe/252Atk/4HP

I'm not all that great, though, so it's up to you.

 

[Ezkayl]

Starmie was definately on my list for the last spot so that's probably what i'll take as for malamar i've been using it in game without any special training and it owns just about anything which is why i like it that's really a preference thing for him the rest are just things i've mulled over, i can see the sense in the advice you've given and will be playing around with my set up, everything is lvl 1 not ev trained or anything yet so the only effort i've put in so far is into the time to breed the right natures etc, so changing plans isn't too much of a hassle yet :)

 

[PlatinumDude]

Hmm a 6th Pokemon. It looks like you need another attacker. You need someone to resist for when they try and take down the Ferrothorn. You have a couple options.

Greninja
Dark Pulse
Ice Beam
Scald
Grass Knot
Nature: +SpA/-Atk
Focus Sash/Life Orb
252Spe 252Atk 4Hp

OR

Talonflame
Brave Bird
Flare Blitz
U-Turn
Flame Charge/Aerial Ace/???
144 HP/252 Atk/112Spe
Choice Scarf/Leftovers
Nature: +Atk/-SpA

Those are just two Pokemon I like. However, I've been using this recently and it's a great water sweeper.

Crawdaunt
Aqua Jet
Crabhammer
Knock Off
Brick Break/Aerial Ace/Swords Dance
Life Orb
Adaptability
Adamant Nature
252Spe/252Atk/4HP

I'm not all that great, though, so it's up to you.

To expand, better sets for each. Greninja needs all the power it can get, so Hydro Pump is the better option over Scald. Scald is better off for defensive Pokemon, IMO:
-Hydro Pump
-Ice Beam
-Extrasensory
-Dark Pulse/Hidden Power (Fire/Grass)/Grass Knot/Spikes
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Life Orb/Focus Sash
Ability: Protean

Better sets for Talonflame here. Flame Charge and Aerial Ace aren't that strong and Talonflame needs the raw power of both Flare Blitz and Brave Bird. Sure, they induce recoil, but that's what Roost is for:
-Flare Blitz
-Brave Bird
-U-turn
-Tailwind/Roost
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Choice Band/Sharp Beak/Sky Plate
Ability: Gale Wings

or
-Swords Dance
-Flare Blitz
-Brave Bird
-Roost
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Life Orb/Sharp Beak/Sky Plate
Ability: Gale Wings

or
-Bulk Up
-Brave Bird
-Roost
-Taunt/Will-o-Wisp
Nature: Careful
EVs: 248 HP/8 Def/252 SDef
Item: Leftovers
Ability: Gale Wings

 

[Ezkayl]

i dunno this culd be a horrible idea but is a thief pokemon any good, not actually for this team but in general, i mean the ability to steal a troublesome pokemons item... is there any merit in the idea?

 

[PlatinumDude]

i dunno this culd be a horrible idea but is a thief pokemon any good, not actually for this team but in general, i mean the ability to steal a troublesome pokemons item... is there any merit in the idea?

There's absolutely no merit in Thief. First off, the Pokemon has to be itemless, which is terrible in the long run; the Pokemon would sorely miss the recovery from Leftovers or the extra power/Speed boost from Life Orb or a Choice item.