I've actually been working on a deck similar to this one. Difference being I run Leafeon as a revenge killer and attack with Druddigon. Basically it's
3-1-2 Vileplume
2-2 Houndoom Prime
3-3 Roserade
4 Druddigon
2-2 Leafeon
1 Umbreon UD
1 Cleffa
4 Rainbow
3 Sp Dark
4 DCE
3 Grass
and your average plume T/S/S line
Just start with Cleffa/Druddigon, collector out your Oddishes and a Roselia while attaching a DCE to Drudd, collector out a Houndour and Eevee next turn while evolving to roserade and gloom/vileplume amd attaching a grass to Druddigon to begin retreat blocking. Next turn confuse/poison with rainbow/Roserade, set up Houndoom with the Burn and Leafeon for the revenge. They can't retreat out of the confuse/burn/poison because of Druddigon and can't switch because of Vileplume. A better version of vanilluxe lock imo.
Best part of it? The only way for them to get out of it is to try and attack. If they flip tails? 30 more damage. Heads? they get to attack but take 20 damage in the process and, if they get a KO, Leafeon comes back for 100-150 damage + the 20 and poison damage.
Umbreon is in there for the Donphan/Primetime games where he becomes your primary/only attacker and you just status condition them for the win.
I haven't playtested it yet (League is tomorrow) BUT it seems fast and solid in theory
Also, to those saying 90 HP is low for a main attacker: It is, but 110 HP (Yanmega/Tornadus) and 100 (Cinccino) is pretty bad too. anything below 130 is OHKO territory, period. Building a deck that's fast enough to compensate is what really matters. And a basic leafeon/roserade deck can start hitting for 100 on t2. Eevee even has built in search power!