So before you start tearing this team apart, there are a few guidelines that I should share. I don't like the idea of using legendaries (even the ones in OU), or any dragons at all. I don't necessarily think they're overpowered or anything, but I just think the dragon type is lame. I would also never use Gyarados, Tyranitar, Blissey, or Skarmory because they're so common and I don't respect them as pokemon. It's difficult making teams, because I'll see that a Heatran or a Tyranitar would be a perfect compliment, but trust me when I say that I'm completely set in my ways. So, briefly:
-No legendaries
-No dragon-types
-No Gyarados, Tyranitar, Blissey, or Skarmory
-All other pokemon are fair game, and I'll gladly take recommendations for swaps
-While a lot of the movesets here are somewhat standard, I'm a big fan of the unexpected and unconventional. This is kind of an infant-stage "rough draft" if you will, and I want some guidance for what direction to take it in before I get too crazy.
Mamoswine (Lead)
Adamant
Snow Cloak/Oblivious
252 Atk / 252 Spe / 4 HP
@Focus Sash
-Stealth Rock
-Protect
-Earthquake
-Ice Shard
I think this is a pretty common leading set for Mamoswine. I opted for Protect over Endeavor out of personal preference; I like to have the option of scouting when I'm on uncertain ground. Not necessarily a suicide lead, but as of now he's the only one with Stealth Rock so I would push to get that set up unless there's an easy KO. Two of the most common leads, Aerodactyl and Metagross, are dealt with by Ice Shard and Earthquake, respectively.
Rotom-S
Bold
Levitate
252 HP / 80 Def / 88 SpA / 88 Spe
@Leftovers
-Will-O-Wisp
-Air Slash
-Thunderbolt
-Shadow Ball
I usually try to get a Ghost pokemon on my team somewhere for spin-blocking and for predicted fighting/normal moves. I chose Rotom-S for the availability of Air Slash, which I felt was a much-needed attack type for this team--particularly because I will be switching Rotom-S in on attempted fighting attacks directed at Weavile or Mamoswine, or dynamic punches from Machamp (who I otherwise have no effective counter for). Thunderbolt is my best answer to Gyarados, Shadow Ball is STAB-boosted, and Will-O-Wisp is for crippling pursuit-users on the switch.
Starmie
Timid
Natural Cure
252 HP / 216 Spe / 20 Def / 20 SDef
@Leftovers
-Rapid Spin
-Surf
-Ice Beam
-Thunderbolt
My rapid-spinner. The only common offensive move I left out is Psychic because Rotom's Air Slash is already prepared for fighting types. Really the only pokemon I can see it being particularly useful for is Gengar, who Umbreon should be able to switch in on and handle. Starmie is resistant to all of Mamoswine's weaknesses except grass, and even Grass Knot isn't too devastating given Starmie's relatively low weight. Also, since Mamoswine is the lead and leads often set up Stealth Rock, a switch from Mamoswine could also present an opportunity to remove Stealth Rocks before their effect has a chance to accumulate.
I am considering replacing either Ice Beam or Thunderbolt with Recover for survivability. As I see it, Ice Beam is a fallback for dragon-types faster than Infernape after Mamoswine is dead, while Thunderbolt is a fallback for Gyarados in case Rotom-S goes down. I'm not sure if either of them is overkill, and I do already have Wish support for recovery, but I'll mill on it. This is where I could use some advice.
Scizor
Adamant
Technician
252 Atk / 248 HP / 8 Spe
@Life Orb
-U-Turn
-Superpower
-Pursuit
-Bullet Punch
My pursuit user. I don't want to lock myself in for an easy Magnezone kill, so life orb leaves Superpower available without losing too much power. I might instead try an Expert Belt to miscue people into thinking I'm choice-locked. Regardless, I am adamantly opposed to using a choice item on Scizor here because he is my only pursuit user and Magnezone would get an easy revenge kill.
Infernape
Naive
Blaze
252 SAtk / 192 Spe / 64 Atk
@Life Orb
-Flamethrower
-Grass Knot
-Close Combat
-HP (Ice)
Infernape is my wall-breaker and is primarily in place to clear the way for a Weavile sweep. Grass Knot is needed here for Swampert, Flamethrower is a good STAB attack and handles Skarmory, and Close Combat handles special walls (many of whom happen to be normal-type). Ice is here for dragon-types, for Gliscor who would otherwise wall this set, and for generally good offensive coverage.
Umbreon
Sassy
Synchronize
252 HP / 252 SDef / 4 Def
@Leftovers
-Yawn
-Wish
-Protect
-Payback
For Wish support, primarily needed by Scizor without Roost, and Yawn for baton chain breaking or anti-stall.
Be gentle.
-No legendaries
-No dragon-types
-No Gyarados, Tyranitar, Blissey, or Skarmory
-All other pokemon are fair game, and I'll gladly take recommendations for swaps
-While a lot of the movesets here are somewhat standard, I'm a big fan of the unexpected and unconventional. This is kind of an infant-stage "rough draft" if you will, and I want some guidance for what direction to take it in before I get too crazy.
Mamoswine (Lead)
Adamant
Snow Cloak/Oblivious
252 Atk / 252 Spe / 4 HP
@Focus Sash
-Stealth Rock
-Protect
-Earthquake
-Ice Shard
I think this is a pretty common leading set for Mamoswine. I opted for Protect over Endeavor out of personal preference; I like to have the option of scouting when I'm on uncertain ground. Not necessarily a suicide lead, but as of now he's the only one with Stealth Rock so I would push to get that set up unless there's an easy KO. Two of the most common leads, Aerodactyl and Metagross, are dealt with by Ice Shard and Earthquake, respectively.
Rotom-S
Bold
Levitate
252 HP / 80 Def / 88 SpA / 88 Spe
@Leftovers
-Will-O-Wisp
-Air Slash
-Thunderbolt
-Shadow Ball
I usually try to get a Ghost pokemon on my team somewhere for spin-blocking and for predicted fighting/normal moves. I chose Rotom-S for the availability of Air Slash, which I felt was a much-needed attack type for this team--particularly because I will be switching Rotom-S in on attempted fighting attacks directed at Weavile or Mamoswine, or dynamic punches from Machamp (who I otherwise have no effective counter for). Thunderbolt is my best answer to Gyarados, Shadow Ball is STAB-boosted, and Will-O-Wisp is for crippling pursuit-users on the switch.
Starmie
Timid
Natural Cure
252 HP / 216 Spe / 20 Def / 20 SDef
@Leftovers
-Rapid Spin
-Surf
-Ice Beam
-Thunderbolt
My rapid-spinner. The only common offensive move I left out is Psychic because Rotom's Air Slash is already prepared for fighting types. Really the only pokemon I can see it being particularly useful for is Gengar, who Umbreon should be able to switch in on and handle. Starmie is resistant to all of Mamoswine's weaknesses except grass, and even Grass Knot isn't too devastating given Starmie's relatively low weight. Also, since Mamoswine is the lead and leads often set up Stealth Rock, a switch from Mamoswine could also present an opportunity to remove Stealth Rocks before their effect has a chance to accumulate.
I am considering replacing either Ice Beam or Thunderbolt with Recover for survivability. As I see it, Ice Beam is a fallback for dragon-types faster than Infernape after Mamoswine is dead, while Thunderbolt is a fallback for Gyarados in case Rotom-S goes down. I'm not sure if either of them is overkill, and I do already have Wish support for recovery, but I'll mill on it. This is where I could use some advice.
Scizor
Adamant
Technician
252 Atk / 248 HP / 8 Spe
@Life Orb
-U-Turn
-Superpower
-Pursuit
-Bullet Punch
My pursuit user. I don't want to lock myself in for an easy Magnezone kill, so life orb leaves Superpower available without losing too much power. I might instead try an Expert Belt to miscue people into thinking I'm choice-locked. Regardless, I am adamantly opposed to using a choice item on Scizor here because he is my only pursuit user and Magnezone would get an easy revenge kill.
Infernape
Naive
Blaze
252 SAtk / 192 Spe / 64 Atk
@Life Orb
-Flamethrower
-Grass Knot
-Close Combat
-HP (Ice)
Infernape is my wall-breaker and is primarily in place to clear the way for a Weavile sweep. Grass Knot is needed here for Swampert, Flamethrower is a good STAB attack and handles Skarmory, and Close Combat handles special walls (many of whom happen to be normal-type). Ice is here for dragon-types, for Gliscor who would otherwise wall this set, and for generally good offensive coverage.
Umbreon
Sassy
Synchronize
252 HP / 252 SDef / 4 Def
@Leftovers
-Yawn
-Wish
-Protect
-Payback
For Wish support, primarily needed by Scizor without Roost, and Yawn for baton chain breaking or anti-stall.
Be gentle.