Rate my singles team? :)

[Oweena]

I've only used this team once, and it worked pretty well. However I didn't really get a chance to test them all, as whimsicott and escavalier managed to stall my friend's entire team... I'm open to suggestions though!


Whimsicott @ Big Root
Prankster
252 defense / 252 sp.defense
Timid
- Giga Drain
- Encore
- Leech Seed
- Substitute


Escavalier @ Leftovers
Shell Armor
252 HP / 126 defense / 126 sp.defense
Jolly (I realise this is kind of pointless, but I got fed up of breeding...)
- X-Scissor
- Toxic
- Iron Head
- Protect


Jellicent @ Choice Scarf
Water Absorb
252 sp.attack / 252 speed
Modest
- Water Spout
- Shadow Ball
- Ice Beam
- Scald


Garchomp @ Choice Band
Sand Veil
252 attack / 252 speed
Jolly
- Earthquake
- Outrage
- Dragon Claw
- Rock Slide


Camerupt @ Custap Berry
Solid Rock
252 attack / 252 sp.attack
Serious
- Earth Power
- Endure
- Flamethrower
- Explosion


Milotic @ Rocky Helmet (Wasn't sure what else to give it...)
Marvel Scale
252 HP / 252 defense
Modest
- Scald
- Recover
- Light Screen
- Ice Beam

I was going to give Milotic a Rest and Sleep Talk set, but I had already put it onto White before I realised that Sleep Talk was no longer a TM...

 

[jamiemoore2]

First, I have a question: What tier is this team intended for?

I'm going to assume the Uber tier considering you have Garchomp on your team. I'm going to take this into consideration while rating your team (You should probably edit your post and state the tier).

Anyway, onto the team:

Whismicott:

Not really a good Pokémon in the Uber tier let alone a lead. I recommend replacing him for something better. Might I suggest something like lead Swampert with the following set:

Swampert @ Leftovers
Ability: Torrent
Relaxed Nature [+Def, -Spe]
EVs: 248 HP / 216 Def / 44 SpDef

Moves:
Stealth Rock
Earthquake
Ice Beam
Roar

With access to Stealth Rock and being weak to only Grass type attacks, Swampert is a great choice for a lead. A relaxed nature helps improve Swampert's bulk which can be helpful mid-to-late game as he is also a reliable tank. Stealth Rock is the most important move on the set (all teams should have a Stealth Rock user) closely followed by Roar. The trick is to use Stealth Rock followed by Roar causing Stealth Rock damage to whomever is forced in. Earthquake provides Swampert with a good STAB move while Ice Beam gives Swampert the option of hitting common leads such as Focus Sashed Salamence for super-effective damage. If you want Swampert to be more defensive you could opt to replace Roar for Protect, though I prefer to set up Rocks then force a switch. Another option is to replace Roar for Surf which gives Swampert another solid STAB attack. If you don't want to use Swampert as a tank later on, Leftovers could be replaced with either a Life Orb (makes him a decent late-game sweeper) or a Focus Sash which is preferred as it allows Swampert to set up Stealth Rocks without fail as well as survive one super-effective Grass-type attack at full health. However, I still recommend keeping Leftovers as you have other Pokémon on your team that can be more reliable sweepers.

Garchomp:

Garchomp makes an excellent sweeper. However, your current set doesn't make full use of his potential. Below is a set, in my opinion, that makes better use of Garchomp:

Garchomp @ Life Orb
Ability: Sand Veil
Jolly Nature [+Spe, -SpAtk]
EVs: 4 HP / 252 Atk / 252 Spe

Moves:
Swords Dance
Outrage
Earthquake
Stone Edge / Rock Slide / Fire Fang

Garchomp's impressive base speed combined with its awesome base attack makes Garchomp a lethal Swords Dance sweeper. Swords Dance is the most important move on the set as after one or two makes Garchomp capable of tearing through anything. Outrage can be swapped with Dragon Claw if you prefer but I prefer the power (especially in Uber). Earthquake is pretty much staple which hits all that doesn't resist hard. Stone Edge takes slot four (which can be replaced for Rock Slide for accuracy) for extra coverage. It can be replaced with Fire Fang if you want a counter to Ice type Pokémon. Life Orb makes Garchomp's attacks do a lot more damage and should be the first item choice for this set.

 

[PlatinumDude]

I'll assume this is UU, since most of your Pokemon appear to be there; I'll have to replace Garchomp with something else because it's Uber, as explained later. And if you don't mind my asking, is this supposed to be a Wi-Fi team?

Don't use max Defense/max Special Defense on a defensive/support Pokemon, like Whimsicott. You'll have to max HP before going for one of the defenses. Also, Whimsicott's Special Attack is a bit mediocre to use offensive moves with:
-Encore
-Leech Seed
-Substitute/U-turn
-Taunt/Stun Spore
Nature: Impish
EVs: 252 HP/252 Def/4 SDef
Item: Leftovers
Ability: Prankster

As far as I'm concerned, Escavalier is better off with Megahorn over X-Scissor (you can get Megahorn by breeding Karrablast/Escavalier with Scolipede or Heracross) for more power. And, just a breeding tip, you can give the parent with the desired nature the Everstone (preferably Adamant or Careful) to increase the chances of that nature to be passed down:
-Megahorn
-Iron Head
-Toxic
-Pursuit
Nature: Careful
EVs: 248 HP/8 Atk or Def/252 SDef
Item: *whatever you want, preferably Leftovers*
Ability: Swarm
(this particular Escavalier set can be obtained by breeding Karrablast/Escavalier with Scolipede, who is capable of learning both Megahorn and Pursuit by level up)

Whlie Choice Scarf Jellicent is rather good in VGC, it's not that effective in singles. And since I'm assuming it's a UU team, I'll have to replace it with something else, like Swampert, as suggested above (this Swampert can be obtained by teaching it or any of its pre-evolved forms Stealth Rock in Gen IV, then transferring it over via Poke Transfer).

In UU, Camerupt is outclassed by other Fire Pokemon. Chandelure or Darmanitan are viable replacements, IMO, because they're faster than Camerupt and can hit harder:

Chandelure:
-Fire Blast
-Shadow Ball
-Substitute
-Pain Split
Nature: Timid/Modest
EVs: 4 Def/252 SAtk/252 Spe
Item: Life Orb/Leftovers
Ability: Flash Fire

Darmanitan:
-Flare Blitz
-U-turn
-Rock Slide
-Earthquake/Superpower
Nature: Adamant/Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Life Orb/Choice Band/Choice Scarf
Ability: Sheer Force

Use Toxic over Light Screen on Milotic as a way to break down walls.

Edit @below: thanks; didn't see those.

 

[Hikamaru]

I'll assume this is UU, since most of your Pokemon appear to be there; I'll have to replace Garchomp with something else because it's Uber, as explained later. And if you don't mind my asking, is this supposed to be a Wi-Fi team?

Don't use max Defense/max Special Defense on a defensive/support Pokemon, like Whimsicott. You'll have to max HP before going for one of the defenses. Also, Whimsicott's Special Attack is a bit mediocre to use offensive moves with:
-Encore
-Leech Seed
-Substitute/U-turn
-Taunt/Stun Spore
Nature: Impish
EVs: 252 HP/252 Def/4 SDef
Item: Leftovers
Ability: Prankster

As far as I'm concerned, Escavalier is better off with Megahorn over X-Scissor (you can get Megahorn by breeding Karrablast/Escavalier with Scolipede or Heracross) for more power. And, just a breeding tip, you can give the parent with the desired nature the Everstone (preferably Adamant or Careful) to increase the chances of that nature to be passed down:
-Megahorn
-Iron Head
-Toxic
-Pursuit
Nature: Careful
EVs: 248 HP/8 Atk or Def/252 SDef
Item: *whatever you want, preferably Leftovers*
Ability: Swarm
(this particular Escavalier set can be obtained by breeding Karrablast/Escavalier with Scolipede, who is capable of learning both Megahorn and Pursuit by level up)

Whlie Choice Scarf Jellicent is rather good in VGC, it's not that effective in singles. And since I'm assuming it's a UU team, I'll have to replace it with something else, like Swampert, as suggested above (this Swampert can be obtained by teaching it or any of its pre-evolved forms Stealth Rock in Gen IV, then transferring it over via Poke Transfer).

In UU, Camerupt is outclassed by other Fire Pokemon. Chandelure or Darmanitan are viable replacements, IMO, because they're faster than Camerupt and can hit harder:

Chandelure:
-Fire Blast
-Shadow Ball
-Substitute
-Pain Split
Nature: Timid/Modest
EVs: 4 Def/252 SAtk/252 Spe
Item: Life Orb/Leftovers
Ability: Flash Fire

Darmanitan:
-Flare Blitz
-U-turn
-Rock Slide
-Earthquake/Superpower
Nature: Adamant/Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Life Orb/Choice Band/Choice Scarf
Ability: Sheer Force

Use Toxic over Light Screen on Milotic as a way to break down walls.

Also, what are your Pokemon's natures? For instance, is Milotic Bold? Is Whimsicott Impish? etc.

@PlatinumDude The natures of Oweena's Pokemon:

Whimsicott - Timid
Escavalier - Jolly
Jellicent - Modest
Garchomp - Jolly
Camerupt - Serious
Milotic - Modest