Oh cool, I didn't get a chance to vote, but I would have chosen Dry Skin Escavalier regardless. It's one of those changes of brilliance if you ask me. I just love the irony of making what would normally be a drawback a moot point considering it dies to Fire attacks outright.
Anyway I see a pretty awesome core with Escavalier, Heatran and Landorus-T. Escavalier absorbs Water attacks for the other two and bulky all around, Heatran absorbs Fire attacks and is generally specially defensive and spreads burns with WoW as well as Roar out set-up sweepers, and Lando-T is immune to Ground and resists Fighting for them while packing Intimidate and is good physically defensive. I'd probably run a Scarf on Lando here.
The biggest problem to the core would be Mega Gyarados who just rips through all three with +1 Mold Breaker Waterfall/Earthquake.
As for sets for the snail, it really comes down to Assault Vest and Choice Band.
Escavalier@Assault Vest
Dry Skin
Careful/Adamant 252 HP / 4 At / 252 SpD
Adamant 252 HP / 252 At / 4 SpD
~ Iron Head
~ Megahorn/X-Scissor
~ Knock Off
~ Drill Run/Facade
252 SpA Life Orb Thundurus Thunderbolt vs. 252 HP / 252+ SpD Assault Vest Escavalier: 87-103 (25.2 - 29.9%) -- guaranteed 4HKO
252 SpA Choice Specs Latios Draco Meteor vs. 252 HP / 252+ SpD Assault Vest Escavalier: 74-87 (21.5 - 25.2%) -- 0.1% chance to 4HKO
252 SpA Choice Specs Latios Hidden Power Fire vs. 252 HP / 252+ SpD Assault Vest Dry Skin Escavalier: 228-272 (66.2 - 79%) -- guaranteed 2HKO That's honestly amazing.
252 Atk Escavalier Megahorn vs. 4 HP / 0 Def Latios: 486-572 (160.9 - 189.4%) -- guaranteed OHKO
252+ Atk Escavalier Pursuit vs. 4 HP / 0 Def Latios: 238-280 (78.8 - 92.7%) -- 37.5% chance to OHKO after Stealth Rock
252 SpA Choice Specs Keldeo Secret Sword vs. 252 HP / 0 Def Escavalier: 199-235 (57.8 - 68.3%) -- guaranteed 2HKO
252+ Atk Escavalier Drill Run vs. 0 HP / 0 Def Keldeo: 108-128 (33.4 - 39.6%) -- guaranteed 3HKO
Unfortunately Secret Sword will 2HKO if you try to switch into that, meaning it isn't safe switching into a Keldeo that isn't already spamming Hydro Pump. Best move you can use on him is Drill Run, or Pursuit as he leaves from trapped into Hydro Pump.
252+ Atk Escavalier Facade (140 BP) vs. 252 HP / 0 Def Rotom-W: 163-192 (53.6 - 63.1%) -- guaranteed 2HKO after Leftovers recovery
With Facade you'll be able to handle Rotom-W who unless it has Pain Split has no choice but to Volt Switch out, but Facade here means Escavalier won't be a sitting duck, even if it would more likely be a 3HKO against physical variants.
252 SpA Life Orb Sheer Force Landorus Earth Power vs. 252 HP / 252+ SpD Assault Vest Escavalier: 107-126 (31.1 - 36.6%) -- 63.3% chance to 3HKO
4 Atk Escavalier Knock Off (97.5 BP) vs. 4 HP / 0 Def Landorus: 99-117 (30.9 - 36.5%) -- 63.9% chance to 3HKO
4 Atk Escavalier Iron Head vs. 4 HP / 0 Def Landorus: 123-145 (38.4 - 45.3%) -- guaranteed 3HKO
Escavalier can manage to Knock Off Lando-I's Life Orb making him much easier to handle. You can always 2HKO with max Adamant Iron Head though.
I think there's a sweet spot between At and SpD EVs because Escavalier needs to remain bulky enough to turn these special hits into 3HKOs and remain strong enough to 2HKO himself. The problem is his coverage is poor, and he's SO slow he'll always take two hits no matter what you switch into, even Slowbro!
4 Atk Escavalier Megahorn vs. 4 HP / 0 Def Greninja: 234-276 (81.8 - 96.5%) -- guaranteed 2HKO
4 Atk Escavalier Drill Run vs. 4 HP / 0 Def (Fire type) Greninja: 208-246 (72.7 - 86%) -- guaranteed 2HKO
252 SpA Life Orb Protean Greninja Hidden Power Fire vs. 252 HP / 252+ SpD Assault Vest Dry Skin Escavalier: 255-302 (74.1 - 87.7%) -- 6.3% chance to OHKO after Stealth Rock
The balance here is so delicate for example. You need all the SpD investment you can get to survive that HP Fire, and even with Life Orb recoil Drill Run isn't guaranteed to KO.
Anyway I see a pretty awesome core with Escavalier, Heatran and Landorus-T. Escavalier absorbs Water attacks for the other two and bulky all around, Heatran absorbs Fire attacks and is generally specially defensive and spreads burns with WoW as well as Roar out set-up sweepers, and Lando-T is immune to Ground and resists Fighting for them while packing Intimidate and is good physically defensive. I'd probably run a Scarf on Lando here.
The biggest problem to the core would be Mega Gyarados who just rips through all three with +1 Mold Breaker Waterfall/Earthquake.
As for sets for the snail, it really comes down to Assault Vest and Choice Band.
Escavalier@Assault Vest
Dry Skin
Careful/Adamant 252 HP / 4 At / 252 SpD
Adamant 252 HP / 252 At / 4 SpD
~ Iron Head
~ Megahorn/X-Scissor
~ Knock Off
~ Drill Run/Facade
252 SpA Life Orb Thundurus Thunderbolt vs. 252 HP / 252+ SpD Assault Vest Escavalier: 87-103 (25.2 - 29.9%) -- guaranteed 4HKO
252 SpA Choice Specs Latios Draco Meteor vs. 252 HP / 252+ SpD Assault Vest Escavalier: 74-87 (21.5 - 25.2%) -- 0.1% chance to 4HKO
252 SpA Choice Specs Latios Hidden Power Fire vs. 252 HP / 252+ SpD Assault Vest Dry Skin Escavalier: 228-272 (66.2 - 79%) -- guaranteed 2HKO That's honestly amazing.
252 Atk Escavalier Megahorn vs. 4 HP / 0 Def Latios: 486-572 (160.9 - 189.4%) -- guaranteed OHKO
252+ Atk Escavalier Pursuit vs. 4 HP / 0 Def Latios: 238-280 (78.8 - 92.7%) -- 37.5% chance to OHKO after Stealth Rock
252 SpA Choice Specs Keldeo Secret Sword vs. 252 HP / 0 Def Escavalier: 199-235 (57.8 - 68.3%) -- guaranteed 2HKO
252+ Atk Escavalier Drill Run vs. 0 HP / 0 Def Keldeo: 108-128 (33.4 - 39.6%) -- guaranteed 3HKO
Unfortunately Secret Sword will 2HKO if you try to switch into that, meaning it isn't safe switching into a Keldeo that isn't already spamming Hydro Pump. Best move you can use on him is Drill Run, or Pursuit as he leaves from trapped into Hydro Pump.
252+ Atk Escavalier Facade (140 BP) vs. 252 HP / 0 Def Rotom-W: 163-192 (53.6 - 63.1%) -- guaranteed 2HKO after Leftovers recovery
With Facade you'll be able to handle Rotom-W who unless it has Pain Split has no choice but to Volt Switch out, but Facade here means Escavalier won't be a sitting duck, even if it would more likely be a 3HKO against physical variants.
252 SpA Life Orb Sheer Force Landorus Earth Power vs. 252 HP / 252+ SpD Assault Vest Escavalier: 107-126 (31.1 - 36.6%) -- 63.3% chance to 3HKO
4 Atk Escavalier Knock Off (97.5 BP) vs. 4 HP / 0 Def Landorus: 99-117 (30.9 - 36.5%) -- 63.9% chance to 3HKO
4 Atk Escavalier Iron Head vs. 4 HP / 0 Def Landorus: 123-145 (38.4 - 45.3%) -- guaranteed 3HKO
Escavalier can manage to Knock Off Lando-I's Life Orb making him much easier to handle. You can always 2HKO with max Adamant Iron Head though.
I think there's a sweet spot between At and SpD EVs because Escavalier needs to remain bulky enough to turn these special hits into 3HKOs and remain strong enough to 2HKO himself. The problem is his coverage is poor, and he's SO slow he'll always take two hits no matter what you switch into, even Slowbro!
4 Atk Escavalier Megahorn vs. 4 HP / 0 Def Greninja: 234-276 (81.8 - 96.5%) -- guaranteed 2HKO
4 Atk Escavalier Drill Run vs. 4 HP / 0 Def (Fire type) Greninja: 208-246 (72.7 - 86%) -- guaranteed 2HKO
252 SpA Life Orb Protean Greninja Hidden Power Fire vs. 252 HP / 252+ SpD Assault Vest Dry Skin Escavalier: 255-302 (74.1 - 87.7%) -- 6.3% chance to OHKO after Stealth Rock
The balance here is so delicate for example. You need all the SpD investment you can get to survive that HP Fire, and even with Life Orb recoil Drill Run isn't guaranteed to KO.