Rate my Reg set I Sun team!... 1200 elo reached!!

Question

Koraidon @ Clear Amulet
Ability: Orichalcum Pulse
Tera Type: Fire
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Dragon Claw
- Collision Course
- Protect
- Flare Blitz

Since I got a tailwind setter (he's at bottom) we don't need scale shot or flame charge on him and instead put high power moves which all get a 50% boost! (Sun + STAB), Clear Amulet & Protect to make sure incinaroar isn't a problem and kill it with collision coarse. I will also like an EV spread, I don't need the speed investment so what should I put some of it in?

Meowscarada @ Choice Band
Ability: Protean
Tera Type: Ice
EVs: 252 Atk / 252 Spe
Jolly Nature
- Flower Trick
- Thunder Punch
- U-turn
- Triple Axel

I freaking love this guy, and if you know me you know. Flower trick to stop the ever spreading kyogres, Thunder Punch for Peliper and Ho-oh. Triple axel for sash breaking and landorus, And it has a really good defensive typing (hear me out) it cant be affected my prankster or spore, and rage powder making it a force to be reconned with - so no encores, spores, rage powders, parting shot etc.

Greninja @ Choice Specs
Ability: Protean
Tera Type: Ground
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Water Shuriken
- U-turn
- Tera Blast
- Weather Ball

Its has an ability to change its type and a move that deals HUGE damage in any weather, so no matter the weather, weather ball will be STAB! tera ground to defend itself against miraidon and tera blast to kill it (not a OHKO though.) and sunny weather balls OHKO calyrex.

Goodra-Hisui @ Maranga Berry
Ability: Shell Armor
Tera Type: Fairy
EVs: 4 HP / 252 Def / 252 SpD
Sassy Nature
IVs: 0 Atk
- Shelter
- Life Dew
- Body Press
- Flash Cannon

TANK! can be dangerous when set up and has a good matchups into tanky pokemon like incinaroar with body press and flash cannon to deal with fairies (and its my only super effective move against them), life dew to heal, tera fairy + shell armor + sun makes both forms of Urshifu's STAB not very effective. Maranga berry is the only way to increase Sp.D making it bulkier on the special side. So its bulky on the Special and Physical side and hitting hard of both too!

Garganacl @ Leftovers
Ability: Purifying Salt
Tera Type: Ghost
EVs: 252 HP / 4 Atk / 252 Def
Relaxed Nature
IVs: 0 Spe
- Salt Cure
- Protect
- Wide Guard
- Recover

Its a more reliable physical tank than goodra with amazing synergy with koraidon. Wide guard for calyrex'es and the synergy with koraidon is that its water type weakness is gone in the sun and any water type that wants rain will have to face salt cure, but also Koraidons Flare Blitz pressures calyrex to tera water but is on a timer while glacial lances are ineffective against wide guard. But there is one not water type pokemon that can sets up rain with ease... Tornadus but the guy below can handle him:

Roaring Moon @ Booster Energy
Ability: Protosynthesis
Level: 50
Tera Type: Poison
EVs: EVs: 60 HP / 220 SpD / 228 Spe
Jolly Nature
- Protect
- Tailwind
- Knock Off
- Sunny Day

Sorry for the weird EV's but it lets you to get Protosynthesis speed and enough bulk to survive barely a choice spec max special attack kyogre, now about tornadus: lets say the send out tornadus and kyogre and they use tailwind and ice water spout, roaring moon would outspeed tailwind kyogre by 1 and use sunny day and collision course and win me the game!

I worked so hard for this 1200 elo, now help me get to 1300!

Answer 1

Firstly, Reg I is a dual restricted format so you should have 2 of those. Secondly, there are a lot of problems with the team. I'll go through each Pokemon in order.
Koraidon:
Use Wolfe Glick's LO set, much more effective and powerful. I know you said that you don't need Flame Charge, but you won't always have Roaring Moon next to it to set the TW. Basically, max speed with Jolly nature and max attack. Moves are CC, Flame Charge, Protect and Flare Blitz. No Dragon Claw because Dragon isn't a great offensive typing with so many Tera Fairy and Steel Pokemon, and Dragon Claw isn't that strong. CC over Collision Course because it has higher BP so its more consistent and can give you more OHKOs on important targets.
Wolfe's Set (I think):
Koraidon @ Life Orb
Ability: Orichalcum Pulse
Level: 50
Tera Type: Fire
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Close Combat
- Protect
- Flare Blitz
- Flame Charge

Meowscarada --> Ogerpon (Hearthflame or Cornerstone):
I know that Meowscarada is your favourite Pokemon, but its really not good for your team. Your team is a sun team centred around Koraidon, and a Grass Type not resistant to Fire or providing really high value is not worth it. So, I'm suggesting Ogerpon Rock or Fire. Fire because it will get an extra boost to its damage while still being able to OHKO Kyogre with Wood Hammer or have a ~25% OHKO chance with Horn Leech on a common set and OHKOing CIR with a sun boosted Ivy Cudgel. Ogerpon Rock has better coverage into the mentioned Pelipper while hitting Ho-oh for 4x damage, while not being weak to Fire and still being able to OHKO Kyogre. It also has Follow Me, an incredible supporting move, which combined with Ogerpon Rock's Sturdy, is really good for supporting your Koraidon.
My Set (I don't really use this):
Ogerpon-Cornerstone (F) @ Cornerstone Mask
Ability: Sturdy
Level: 50
Tera Type: Rock
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Wood Hammer
- Ivy Cudgel
- Spiky Shield
- Follow Me

Greninja --> Flutter Mane
Although Specs Flutter won't OHKO CIR in 1 hit without SpA Booster, it can actually with a Stellar or Ghost Tera. You mentioned Greninja almost OHKO's Miraidon with Tera Blast, but Flutter Mane has STAB Moonblast that has a guarenteed OHKO. Additionally, Flutter Mane has tons of different sets so if its not open teamsheets, your opponent may not know what to use to deal with it. Also, it has Protosynthesis and benefits greatly from sun. If you run Sash instead, you could run Icy Wind instead to support Koraidon more. I won't add a set because its really versatile and up to you on how you want to use it.
Goodra-H --> Another Restricted:
As mentioned before, Reg I is a dual restricted format so you need another restricted. I'd recommend a bulky Pokemon like Terapagos or Lunala to give your team another option in Trick Room so you aren't so weak to it. Although, its up to you to decide, I don't really know. Though, CIR would work well with my next change...
Garganacl --> Scraggy (mainly for if you use CIR) :
I'm not too sure on what else could be better because of the very specific niche you put it in, but you could add a counter to CIR that doesn't need Koraidon to win. Instead, you could use a Pokemon with TR + Imprison to flat out prevent it from using TR and even if it Tera's, you can always CC and attack. Or, hear me out, use Scraggy. Min speed underspeeds CIR, can attack back with STAB Foul Play (252+ Atk Scraggy Foul Play vs. 252 HP / 0 Def Calyrex-Ice: 152-180 (73.4 - 86.9%) -- guaranteed 2HKO) and with Eviolite, it survives Glacial Lance, even at plus 2 for CIR:
252+ Atk Calyrex-Ice Glacial Lance vs. 252 HP / 84+ Def Eviolite Scraggy: 73-87 (46.4 - 55.4%) -- 67.6% chance to 2HKO
And it can use Coaching to buff your Koraidon if you want. Also it learns Taunt to stop TR perhaps and Fake Out for utility. Maybe your second restricted could be Calyrex-I with Scraggy?
My Set:
Scraggy @ Eviolite
Ability: Intimidate
Level: 50
Tera Type: Poison
EVs: 252 HP / 84 Def / 172 SpD
Relaxed Nature
IVs: 0 Spe
- Taunt
- Coaching
- Fake Out
- Foul Play

Roaring Moon:
I think just change Protect to Acrobatics, Flying rather than Poison Tera and Max speed (Jolly) and 220 EVs into attack for Speed Booster with Max attack. And most Kyogre's don't run Specs so your safe to leave behind that calc, and you also never mentioned the details of the calc, not even the move. You could also run Taunt instead of Sunny Day... Also, you probably don't need the Booster Energy because you have sun.
**EDIT: Added sets and more detail

Answer 2

Koraidon needs Life Orb and Close Combat, otherwise it doesn't have the damage needed to keep up. Also Goodra is just too slow to work on this team, so switch it for Incineroar to help support the team more

Incineroar @Rocky Helmet
Ability: Intimidate
Tera: Grass
EVs: HP: 252, Def: 4, Sp. Def: 252
Nature: Careful
Moves:
-Fake Out
-Knock Off
-Parting Shot
-Wil-o-Wisp