I will have to disagree with Dresden on his move-sets. 3 Dragon Dancers is a bit much, also you have no special sweepers.
I'd recommend keeping Dragonite as a support pokemon on a pure-Dragon team. Thunder Wave/Toxic, Light Screen, Dragon Claw, Roost. Most Ice-users hit from the special spectrum so you may get use out of Light Screen. T-wave can hit a speedy water type attempting to ruin your fun.
Though not a Dragon type, you may want to use Bulky-Gyara. He fits the theme and won't suffer a 4x Ice weakness.
Use Yache-Berry on Garchomp to counter anything trying to ruin your sweep.
Toxic-Stall Flygon could be fun to try out. Other than that I'd recommend trying a Life Orb set-up using a Rash/Naiive nature. Draco Meteor, Fire Blast/FT, EQ and Roost. This set works better as a surprise set in competitive play, but it may add some more diversity to your line-up. This last thing you want is for all your pokemon to feel the exact same. Makes the game a bit boring.
DDMence is fine.
Use Kingdra however you see fit. DD is a great set-up, but you might prefer a Special-set combined with the Sniper ability.
Honestly, Pure Dragon isn't going to be the best team, but try to diversify them at least. Making them all CC pure physical DD sets will really bore you especially on an in-game team. Since this is in-game you probably won't need Dragonite's supporting moves outside of the Battle Frontier. If you plan on not using D-Nite in BF, use the Mix-set with Roost and Life Orb. - FT, Dragon Pulse, Super Power, Roost.
Help out with my team too!
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