I'm going to try and answer some of your questions as good as I possibly can, hope you learn a thing or 2!
Scarf vish calc:
252+ Atk Strong Jaw Dracovish Fishious Rend (170 BP) vs. 252 HP / 252+ Def Eviolite Corsola-Galar: 171-202 (52.7 - 62.3%) -- guaranteed 2HKO after Stealth Rock
252+ Atk Choice Band Strong Jaw Dracovish Fishious Rend (170 BP) vs. 252 HP / 252+ Def Eviolite Corsola-Galar: 255-301 (78.7 - 92.9%) -- 37.5% chance to OHKO after Stealth Rock
https://www.smogon.com/dex/ss/pokemon/clefable/
https://www.smogon.com/forums/threads/clefable-qc-0-3.3658607/
I would also not run venoshock and toxic, Toxtricity isn't the fastest pokémon and you're better of with using Shift Gear as setup move or 2 other attacks. Some attacks you can run on it are Snarl, Volt Switch, Sludge Wave or Fire punch (on a Shift Gear set)
Corsola-G is an extremely passive mon. If you want to run either of the screens, your opponent most of the time won't have trouble just stalling them out because of the reason you are stalling them out for them. The main benefit of Light Screen and Reflect are to give offensive Pokémon extra bulk so they have an easier time setting up/breaking the opponent's team. While it does sound amazing to have a Corsola-G with Eviolite and Screens up, you're opponent won't feel extra threatened because the way to deal with Corsola-G is just set on hold rather than making Corsola-G the unkillable machine you might think it becomes.1: Galarian Corsola is already stupid bulky, but it also gets light screen and reflect. Why have there been no sets running this? Ik it’s probably because corsola only really has one move slot it can change around, as 3 moves are basically required (Nightshade, Will’O’Wisp, and Strength sap,) so why haven’t people put light screen in the final slot because corsola is already great at destroying physical Pokémon, so a 50% decrease from special moves means that corsola won’t die. Also, if you have a prankster grimmsnarl use light screen and reflect before you send out corsola, you don’t need those moves on corsola.
It's only an emegency check and only IF Dracovish is Scarf AND you are at high HP. As soon as it Choice Band or Rain boosted you have a chance of being OHKOed. The damage from scarf is too high to switch in. If vish kills a thing and you come in for free, he can just switch out and chip Corsola-G down until it is in range. Also, Corsola-G's is way lower than the usage Water Absorb and Storm Drain Pokémon have right now, so it's just better to keep them as a Dracovish check rather than trying to fit Corsola in as an non-answer2: Why has no one used galarian corsola against the fish himself? Scarf fish is a 2HKO, so if you use strength sap you will lower the fish’s attack by 33.3%, and heal back all health from fishious rend. Use it again to guarantee living the next hit + make his attack half of normal (142 to 71) and you can wear him down from there with night shade. If it’s banded fish, it’s around a 40% to OHKO, so use strength sap 2-3 times to lower the fish’s attack enough to where you are safe. Ik that water absorb and storm drain Pokémon are way better, but not everyone is going to have a Pokémon with either of those abilities, while corsola is a Pokémon most people have.
Scarf vish calc:
252+ Atk Strong Jaw Dracovish Fishious Rend (170 BP) vs. 252 HP / 252+ Def Eviolite Corsola-Galar: 171-202 (52.7 - 62.3%) -- guaranteed 2HKO after Stealth Rock
252+ Atk Choice Band Strong Jaw Dracovish Fishious Rend (170 BP) vs. 252 HP / 252+ Def Eviolite Corsola-Galar: 255-301 (78.7 - 92.9%) -- 37.5% chance to OHKO after Stealth Rock
Clefable has been seen running Offensive and Utility sets. For more information I'll refer you to these links:3: Because I am new to competitive Pokémon, I would like to know some sets using clefable. I had no idea that clefable is one of the best Pokémon in the game, so some sets would be helpful.
https://www.smogon.com/dex/ss/pokemon/clefable/
https://www.smogon.com/forums/threads/clefable-qc-0-3.3658607/
The percentage of the opponent not attacking is 70% (60% chance for a flinch + 25% chance for para when he doesn't flinch (40%) -> 60% + 25%*40* = 70%). Togekiss actually is pretty good in the current meta, I would recommend running Heavy Duty Boots or Leftovers so you don't get worn down that easily. Grimmsnarl with Twave can be a good partner to spread the paralysis so Togekiss can come in late game and do his flinch thing. This is of course all luck based and won't work 100% of the time.4: With all of the talk about flinching with galarian darmanitan using icicle crash, it made me think of para-flinch togekiss. Use thunder wave and a move that flinches, and, if you have serene grace, there is a 85% chance of either paralysis or flinching. Idk if bright powder and lax incense are legal, but, if they are, holding either of those will make it a 86.5% chance of not attacking, and that’s if they use 100% accurate moves. For the EVs of my togekiss, I put 252 HP/252 SPE/4 ATK, so it would be fast and bulky.
Toxtricity is a good pokemon but I would recommend using Life orb Or Choice specs over Magnet. The overall damage boost give Boomburst that extra bit of damage that make the ground switchin really fear it.5: I haven’t seen anything with toxtricity, so I will talk about a set for him. Get a toxtricity that’s amped form, and teach it overdrive, boom burst, toxic, and veno shock. It’s ability should be punk rock, and have it hold either throat spray or a magnet. EVs should be 252 SPA/252 SPE/4 HP, so that it is as fast as possible and plenty of special attack for sound moves. There are some counters, such as excadrill and seismitoad, galarian darmanitan, the fish, and bulky Pokémon. However, these attacks are ridiculously strong, and the base power of a boom burst off the get go is 210, while overdrive is 270 base power if you have a magnet. Toxtricity isn’t the best Pokémon, but it’s a good gimmick Pokémon if they don’t have anything to deal with it.
I would also not run venoshock and toxic, Toxtricity isn't the fastest pokémon and you're better of with using Shift Gear as setup move or 2 other attacks. Some attacks you can run on it are Snarl, Volt Switch, Sludge Wave or Fire punch (on a Shift Gear set)
Shuckle has very low base HP stat, meaning it will still get a lot of damage percentage wise when hit by a move. It also doesn't have many support options other than hazards. The lack of recovery and bad defensive typing makes it impossible for Shuckle to reliable wall the Pokémon you think it should wall8: Ik that corsola is probably one of the best tanks, but what about shuckle? Shuckle has worse stats overall than corsola, but his purpose is to be a tank, and, with 230 defense and special defense, he tanks everything. Can anyone tell me why shuckle isn’t used at all (aside from his other terrible stats)