While Life Orb + 3 attacks Scizor seems tempting, Scizor might not be strong enough for the job without some sort of other offensive boost:
-U-turn
-Bullet Punch
-Superpower/Brick Break
-Pursuit/Quick Attack
Nature: Adamant
EVs: 248 HP/252 Atk/8 Spe
Item: Choice Band
Ability: Technician
or
-Swords Dance
-Bullet Punch
-Superpower/Brick Break
-Bug Bite/Roost/Quick Attack
Nature: Adamant
EVs: 252 Atk/4 SDef/252 Spe
Item: Life Orb/Leftovers/Iron Plate/Metal Coat
Ability: Technician
or
-Swords Dance
-Bullet Punch
-Bug Bite/Superpower/Brick Break
-Roost
Nature: Adamant
EVs: 252 HP/40 Atk/216 SDef
Item: Leftovers/Life Orb/Iron Plate/Metal Coat
Ability: Technician
If Latias is using a Calm Mind set, it's better off with a more defensive spread so that it doesn't face competition with Latios (252 HP/4 SAtk/252 Spe). HP Fire or Refresh are also somewhat preferred options over Psyshock.
LightningRod is Raichu's preferred ability now, but you can only get it from events.
While Typhlosion isn't good in OU play, it's better off holding a Choice Scarf and revenging with Eruption:
-Eruption
-Fire Blast/Flamethrower
-Focus Blast
-Hidden Power (Grass/Ice)
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Choice Scarf
Close Combat is the better option over Lucario's Drain Punch because if you choose to use Drain Punch, you lose out on some OHKOs. Sure, the defense drops are annoying, but the higher base power compensates for it.
Hydreigon is best of mixed, when it can break down walls, shielded with Sub to ease prediction with its moves or holding Specs for more immediate power:
-Draco Meteor
-Fire Blast
-Superpower
-Roost/Earthquake/Earth Power/Dark Pulse
Nature: Rash/Mild
EVs: 4 Atk/252 SAtk/252 Spe
Item: Expert Belt/Life Orb
or
-Substitute
-Dragon Pulse
-Focus Blast
-Roost/Fire Blast
Nature: Modest
EVs: 4 HP/252 SAtk/252 Spe
Item: Life Orb/Leftovers
or
-Draco Meteor
-Focus Blast
-Fire Blast/Flamethrower
-U-turn/Dark Pulse
Nature: Modest
EVs: 4 HP/252 SAtk/252 Spe
Item: Choice Specs