i have used most if not all of these Pokemon to great effect. let me give you a few suggestions:
Dragonite @ Leftovers/Yache Berry
Trait: Multiscale
Jolly Nature (+Spd, -SAtk)
EVs: 252 Spd/ 212 Atk/ 44 HP
- Dragon Claw
- ExtremeSpeed
- Superpower
- Roost
This set chooses to pass up on boosting moves to instead invest in recovery and longevity. Leftovers helps keep Multiscale intact in the event of minor damage, or Yache Berry helps tank and Ice attack even if Multiscale is broken. Dragon Claw is STAB and was chosen over Outrage to allow easier use of Roost. Roost is instant recovery, and drops Dragonites Flying type for that turn, making Ice attacks only x2 effective and with Multiscale can easily outstall Blizzard's 8 PP or Ice Beam's 18. ExtremeSpeed is for sniping weakened opponents, and you can also run Adamant Nature to make it hit harder, since ExtremeSpeed bypasses lower Spd. Superpower allows Ice Types to be challenged as long as D-Nite still has Multiscale. One Superpower is usually enough to OHKO most threats, and ExtremeSpeed can finish off any that didn't go down the first time.
Arcanine @ Life Orb
Trait: Flash Fire
Adamant Nature (+Atk, -SAtk)
EVs: 252 Atk/ 252 Spd/ 4 HP
- Flare Blitz
- ExtremeSpeed
- Wild Charge
- Close Combat
this set is an all out attacker. Life Orb boosted STAB Flare Blitz really puts the hurt on stuff. Wild Charge and Close Combat are coverage moves that also hit hard. ExtremeSpeed is used like it is on Dragonite, plus Life Orb pumping its power. Flash Fire was chosen over Intimidate to cover a team member i am going to switch in a bit.
Breloom: is killer, but can't take a hit, and the only real check to Dragon types you have is Dragonite who will most likely break Multiscale on the switch in. i suggest one of my favorite pokemon:
Weavile @ Focus Sash
Trait: Pressure
Adamant Nature (+Atk, -SAtk)
EVs: 252 Atk/ 252 Spd/ 4 HP
- Ice Punch
- Pursuit
- Low Kick
- Ice Shard
Now this thing is pretty good for trapping Psychic and Ghost types, as well as checking x4 Ice weak Dragons (Dragonite, Salamence, Garchomp, Flygon, Rayquaza). the only thing that keeps Weavile from OU is his awful defenses, on par with Gengar, and the fact that his Atk maxes out at 372, while Gengars SAtk maxes out at 394 and Gengar has 3 immunities (Fighting, Normal, and Ground). 4 if you count Toxic immunity. So we give Weavile a Focus Sash to ease this. Ice Punch can OHKO all of the Dragons listed above, Pursuit destroys Alakazam, Gengar, Reuniclus, Mismagius, and the like, while Low Kick makes short work of most Steel types. Ice Shard lets Weavile clean up anything that didn't eat it the turn before.
Lucario: Lucario has decent Spd and good offenses but nothing in the defense department and unless the attack is x4 resisted, he is toast after the lightest scratches. i suggest:
Scizor @ Choice Band
Trait: Technician
Jolly Nature (+Spd, -SAtk)
252 Atk/ 212 Spd/ 144 HP
- Bullet Punch
- U-Turn
- Pursuit/Night Slash
- Superpower
This beast easily outclasses Lucario in the role of a Physical Attacking Steel type due to better typing, and a much better Ability in Technician. Bullet Punch is mean, Superpower hits unbelievably hard after Choice Band. Night Slash or Pursuit is your choice, depending o. whether you trust Weavile as a Trapper or want to save its Focus Sash for Dragon type threats, and rely on Scizors superior Bulk. U-Turn is STAB and Banded dents anything hard. it also serves a purpose since Scizors 1 weakness is Fire. so you can U-Turn out of a Fire attack and throw Arcanine in front of it, which gives STAB Flare Blitz a boost on top of Life Orb.
Skarmory @ Leftovers
Trait: Sturdy
Impish Nature (+Def, -SAtk)
252 Def/ 212 HP/ 44 SDef
- Brave Bird
- Stealth Rock/Spikes
- Whirlwind
- Roost
Spikes is preferred to Stealth Rock, but since Rocks hit more and you don't have another Rock Setter, i understand keeping it. Roost is instant recovery and brave Bird is STAB. Whirlwind is chosen over Taunt since Skarm lacks the Spd to effectively use it.
Kingdra: just needs a little tweaking. for a long time, Kingdra has abused a Specs set. i give you:
Kingdra @ Choice Specs
Trait: Sniper
Modest Nature (+SAtk, -Atk)
EVs: 252 SAtk/ 144 Spd/ 112 HP
- Draco Meteor
- Ice Beam
- Surf
- Dragon Pulse
this set uses Surf and Dragon Pulse as STABs to deal out damage. Ice Beam is Coverage and Draco Meteor abuses the amazing Neutral Coverage Dragon type attacks provide plus a STAB boosted 140 BP and the use of Sniper makes it capable of tearing right through even the Bulkiest Walls. Kingdra is entirely capable of ruining teams just by its menacing presence threatening to strike at any moment.
hopefully this helps. i think you could maybe consider adding another special attacker to the team but that i will leave in your hands.
Hope this helps :)