Scolipede is doing too much. It should stick to either BPing Swords Dance boosts or setting up hazards, not both. It should also use Megahorn as its Bug STAB because of its massive power:
-Spikes
-Toxic Spikes
-Megahorn
-Earthquake/Rock Slide
Nature: Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Focus Sash
Ability: Swarm
or
-Spikes/Toxic Spikes
-Megahorn
-Earthquake
-Rock Slide
Nature: Jolly
EVs: 4 HP/252 Atk/252 Spe
Item: Focus Sash/Life Orb
Ability: Swarm
or
-Swords Dance
-Megahorn
-Earthquake
-Rock Slide/Baton Pass
Nature: Jolly
EVs: 252 Atk/4 Def/252 Spe
Item: Life Orb
Ability: Swarm
Porygon2 is currently using a defensive set, so why not give it a support move over HP Fighting, like Thunder Wave or Toxic? (since BoltBeam is good enough already) Also, this EV spread can be used to help it take special hits a bit more easily: 252 HP/176 Def/80 SDef.
Bronzong is more of a "
Stone Wall," aka something that can take hits very easily given its high defenses and average offenses. Plus, its offensive moves are tied down to its weaker offensive stat (both should only be used in a Calm Mind set). It should also use Levitate as its ability. While avoiding supereffective damage from Fire moves is tempting, a Ground immunity is usually better:
-Stealth Rock
-Toxic
-Gyro Ball
-Earthquake
Nature: Relaxed
EVs: 252 HP/252 Def/4 SDef
Item: Leftovers
Ability: Levitate
or
-Calm Mind
-Psyshock
-Flash Cannon
-Protect/Hidden Power (Ground)
Nature: Bold
EVs: 252 HP/252 Def/4 SDef
Item: Leftovers
Ability: Levitate
While Focus Blast on Nidoking is an alternative way for dealing with Steels, it has redundant coverage with Earth Power. Fire Blast can also hit Steels super effectively, while being more accurate at the same time. You can also use Sludge Wave for a secondary STAB.
Choice Scarf + Swords Dance is a big no-no on Heracross since using both would leave you strapped for coverage and you'll be locked into SD when you use it. Brick Break also isn't good because it's a lot weaker than Close Combat. Use the following moves instead: Stone Edge and Earthquake (though it has redundant coverage with Close Combat, it's Heracross' way of dealing with the Nidos).
Edit: Just by looking at the team, you have a pretty nasty Fire weakness and something like Arcanine or Chandelure can easily blast through it. Pokemon you can consider are Swampert and Milotic (possibly over Scolipede):
Swampert:
-Stealth Rock
-Earthquake
-Scald/Waterfall
-Toxic/Roar
Nature: Relaxed/Impish
EVs: 240 HP/16 Atk/252 Def
Item: Leftovers
Ability: Torrent
Milotic:
-Scald
-Ice Beam
-Recover
-Toxic/Dragon Tail/Haze
Nature: Bold
EVs: 248 HP/252 Def/8 Spe
Item: Leftovers
Ability: Marvel Scale
or
-Rest
-Sleep Talk
-Scald
-Dragon Tail
Nature: Calm
EVs: 248 HP/196 Def/56 SDef/8 Spe
Item: Leftovers
Ability: Marvel Scale