With Hippowdon's current EV spread, is there anything notable that it can outrun? If there's nothing notable, the EV spread should be 252 HP/244 Def/12 SDef.
Rest isn't as useful as it used to be on Swampert. Also, your team has a bit of a Fighting weakness, so Reuniclus or Alakazam can help instead:
Reuniclus:
-Calm Mind
-Psychic/Psyshock
-Focus Blast
-Recover
Nature: Bold
EVs: 252 HP/252 Def/4 SDef
Item: Life Orb
Ability: Magic Guard
or
-Trick Room
-Psychic/Psyshock
-Shadow Ball
-Focus Blast
Nature: Quiet
EVs: 192 HP/64 Def/252 SAtk
Item: Life Orb
Ability: Magic Guard
Alakazam:
-Substitute/Calm Mind
-Psychic/Psyshock
-Shadow Ball
-Focus Blast
Nature: Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Life Orb/Focus Sash
Ability: Magic Guard
Don't use Air Slash on Skarmory; it runs off of its weaker offensive stat. Drill Peck should be in there instead, since you're worried about Brave Bird's recoil. Roar is also blocked by Soundproof (due to it being a sound move), so Whirlwind is the better option. Sturdy should also be the ability to use since it ensures Skarmory will be on the field after taking a fatal hit (it can always be reactivated later with 2 uses of Roost). Also, since Hippowdon is using Stealth Rock, use Spikes instead.
115 Special Attack sometimes isn't enough for Lucario to sweep by itself, so it should be using Nasty Plot. Shadow Ball (or Dark Pulse) should go over Dragon Pulse for virtually perfect coverage. You can use Choice Specs if you want to hit right hard off the bat, if you want. In that case, the moves should be Aura Sphere/Shadow Ball or Dark Pulse/Hidden Power (Ice)/Vacuum Wave.
If Scizor is using Choice Band, its EVs should be focused on its bulk to help it survive as long as it can. In that case, the set should look like this:
-U-turn
-Bullet Punch
-Superpower/Brick Break
-Quick Attack/Pursuit
Nature: Adamant
EVs: 248 HP/252 Atk/8 Spe
Item: Choice Band
Ability: Technician
If Scizor is using SD, use Bug Bite over X-Scissor, since it benefits from the Technician boost:
-Swords Dance
-Bullet Punch
-Bug Bite
-Superpower/Brick Break
Nature: Adamant
EVs: 252 Atk/4 SDef/252 Spe
Item: Life Orb/Leftovers/Iron Plate
Ability: Technician
or
-Swords Dance
-Bullet Punch
-Bug Bite/Superpower/Brick Break
-Roost
Nature: Adamant
EVs: 252 HP/40 Atk/216 SDef
Item: Leftovers/Iron Plate
Ability: Technician
On Heatran, Explosion lost most of its charm in the generation shift to V; it doesn't halve Defense anymore before it hits. The fact that Heatran is using a -Attack nature doesn't help. If Heatran is to be defensive, it should be specially defensive because most of its resistances are Special:
-Lava Plume
-Stealth Rock/Roar
-Will-o-Wisp/Toxic
-Protect
Nature: Calm
EVs: 248 HP/252 SDef/8 Spe
Item: Leftovers
You also have a pretty bad weakness to bulky Waters, so other Pokemon to consider are Ferrothorn and Virizion; you can choose who you can replace for either one:
Ferrothorn:
-Spikes/Stealth Rock
-Leech Seed
-Power Whip/Protect
-Gyro Ball/Thunder Wave/Protect
Nature: Relaxed
EVs: 252 HP/88 Def/168 SDef
Item: Leftovers
Virizion:
-Swords Dance
-Leaf Blade
-Close Combat
-Hidden Power (Ice)/Stone Edge
Nature: Hasty/Naive/Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Life Orb/Leftovers
or
-Calm Mind
-Focus Blast
-Giga Drain
-Hidden Power (Ice)
Nature: Timid
EVs: 4 HP/252 SAtk/252 Spe
Item: Leftovers/Life Orb
or
-Work Up
-Close Combat
-Giga Drain
-Stone Edge/Hidden Power (Ice)
Nature: Hasty/Naive
EVs: 104 Atk/152 SAtk/252 Spe
Item: Leftovers/Life Orb
or
-Reflect
-Light Screen
-Taunt
-Giga Drain/Close Combat
Nature: Timid/Jolly
EVs: 252 HP/4 Def/252 Spe
Item: Light Clay