Issues with the team:
No Protect on any pokemon meaning you can't defend or reposition any your pokemon.
No speed control meaning you will always move before any of your opponent's pokemon.
All pokemon except Dragonite have useless Teras.
Very weak to sleep.
These are my changes:
Dragonite
I gave Dragonite Multiscale to help make sure it doesn't go down when trying to set up and get a Weakness Policy boost. I replaced Fire Punch with Protect so you can reposition into something else to help Protect it. Finally I replaced Earthquake with Stomping Tantrum so you don't kill your other pokemon.
Grimmsnarl
I gave it Tera Ghost to dodge Fake Out in a pinch.
Clefable
I replaced Wish for Life Dew, healing Clefable immediately aswell as healing your partners, which can get Dragonite back into Multiscale range. Then I removed Knock Off for Protect. Knock Off wasn't a bad idea by any means, but you need to keep Clefable alive longer so it can keep supporting the team. I switched Leftovers for Safety Goggles so you don't get sleep spammed on. And finally I gave it Tera Steel to help with it's weaknesses.
Rotom-Wash (Removed)
Rotom-Wash wasn't BAD, but it's role of pivoting and getting burned is done better by a certain cat...
Incineroar
Incineroar isn't called the best Doubles pokemon for nothing, as it gives a ton of support for your team.
Incineroar @Sitrus Berry
Ability: Intimidate
Shiny: Yes
Tera: Ghost
EVs: HP: 252 / Atk: 4 / Sp.Def: 252
Careful Nature
-Fake Out
-Knock Off
-Parting Shot
-Will-O-Wisp
Fake Out shuts down a threat for a turn, Knock Off is main damage source and removes items, Parting Shot can weaken a threat, then safety pivot into something else, and Will-O-Wisp further weakens physical attackers.
Scizor
Switched Brick Break for Swords Dance. Brick Break is Garbage and you need a set up move on Scizor if it's ment to be your back up sweeper. Replaced Bug Buzz with Protect so Scizor can stay safe (also why is that Special move even on a Scizor), I gave it Bug Bite for Technician boosted STAB, and Finally I gave it Tera Water to get rid of the 4x Fire weakness.
Corvinight (Removed)
Corvinight wasn't doing anything useful, and there's still the issue of no speed control, and I know just the flying type to help with that...
Tornadus
Tornadus is a great fit on the team, keeping the Ground immunity and giving you some speed control.
Tornadus @Covert Cloak
Ability: Prankster
Shiny: Yes
Tera: Dark
EVs: HP: 252 / Sp.Atk: 4 / Spd: 252
Timid Nature
-Tailwind
-Bleakwind Storm
-Taunt
-Protect
Tailwind doubles your team's speed, Bleakwind Storm is for damage, Taunt stops Status moves aimed at Dragonite and Scizor, and Protect keeps Tornadus alive. Tera Dark is to stop opposing Prankster Taunt, and Covert Cloak stops Fake Out.
Pokepaste: https://pokepast.es/3921e5973bfa6a16