Ok! So, with the new generation, us Eevee lovers can finally make a full team of non-repeating Eeveelutions, not including the weak, baby Eevee as well. And with that, I'd like to see what everyone around here thinks, as well as give me comments to help develop them a bit better!
Items and EVs have always been a problem for me to decide on, so those are two focuses I need the most help with.

Undine @: Leftovers
Ability: Water Absorb
Nature: Impish
Wish
Substitute
Acid Armor / Surf
Last Resort / Ice Beam
Ok, short explanation here. Wish and Substitute here are an idea for a staller-tank-thing... As for the second two spots, the first ones deal with Glaceon on the team and preserves Vaporeon's tankishness. Acid Armor to boost it's defense and Last Resort, since I'll have already used all 3 other moves to set him up. The second set of moves is for Flareon's inclusion, giving him some power over the types that Glaceon used to cover for.

Volt @: [None]
Ability: Volt Absorb
Nature: Timid
Thunderbolt
Light Screen
Roar
Covet
Here, the idea is to set up some defense for the party (he'll most likely be my lead) then scare off the setup of the other team after snatching their hold item away.

Luna @: Sitrus Berry
Ability: Synchronize
Nature: Quiet
Psychic
Trick Room
Curse
Baton Pass
Now this, I will admit, was a rather novel idea on my part, considering Espeon has the movepool to pull this off. Curse away, upping Attack and Defense and lower Speed. Then, pull out Trick Room, temporarily nulling the Speed reduction and Baton Pass everything off to another Pokemon (probably Leafeon or Flareon).

Shadow @: King’s Rock/Razor Fang
Ability: Synchronize
Nature: Bold
Dark Pulse
Toxic
Swagger
Wish / Moonlight
Rather standard annoyer/staller... Toxic and Swagger to inflict colateral damage, Dark Pulse (plus King's Rock/Razor Fang) for flinching, and Wish for self or switch recovery (Glaceon) or Moonlight for extra healing power (Flareon).

Sylph @: Muscle Band
Ability: Leaf Guard
Nature: Adamant
Leaf Blade
Aerial Ace
X-Scissor
Dig
Helpful and diverse physical sweeper for the team, covering plenty of weaknesses that the Eeveelutions typically couldn't cover in the past. Dig is there for those pesky Electrics (and Steels, if I choose Glaceon). It's surely up for change if someone has a better suggestion, particularly if Flareon comes to be the better choice.

Celsius @: Wise Glasses
Ability: Snow Cloak
Nature: Modest
Hail
Ice Beam
Water Pulse
Shadow Ball
Obviously, a Special Sweeper that can give itself a small evasion boost. Glaceon helps cover the moves that my tanky Vaporeon lacks. Besides making a drastic change to Vaporeon, Glaceon is the only good Special Sweeper for the team, but I'm kinda wishy-washy between this and Flareon...
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Efreet @: Heat Rock
Ability: Flash Fire
Nature: Adamant
Will-O-Wisp
Sunny Day
Fire Fang
Iron Tail
Flareon helps cover some type weaknesses that Glaceon makes awkward to do. Will-O-Wisp to help drop those harsh Physical attacks. Sunny Day is there to boost Fire Fang (which I chose over Flamethrower for its flinching, same with Thunder Fang on Jolteon) as well as initiate Leafeon's Ability. I'm having trouble deciding between Glac or Flar, since Flar gives me more advantages for my team, but a second physical attacker...