Hi! I've played with this team since the day Mega Sableye came out. When I built it, I had 0 competitive experience. As of today, I have 1000+ games with this team, and I just love it. I want to make some EV/ Moveset changes but I desperately don't want to change my pokemon out. Advice is appreciated.
The Team
Sableye (Sableye-Mega) @ Sablenite Ability: Prankster EVs: 252 HP / 120 Def / 136 SpD Calm Nature IVs: 0 Atk - Dark Pulse - Recover - Calm Mind - Will-O-Wisp
Mega Sableye is my team's mega, and I think it does a pretty good job. If they setup with a physical attacker, and I haven't mega'd, it can willl o wisp them. This combined with calm mind lets it win 1v1s against almost everything, especially if they are partially weakened. I regularly get this to +6 with calm mind (mabye not a great thing to do), but it takes hits well. What I would like to improve is the ev spread. It is currently just randomly set so it can be bulky both physically and specially, but I'm not sure how to change it to survive important attacks, or what those attacks are.
Ferrothorn @ Leftovers Ability: Iron Barbs EVs: 252 HP / 252 Def / 4 SpD Relaxed Nature IVs: 0 Spe - Leech Seed - Gyro Ball - Protect - Stealth Rock
Ferrothorn was the last pokemon I added to the team. Full physical investment makes it an absolute wall, and it works well at forcing switches on setup mons by scaring them out with leech seed + protect. It has stealth rock because hazards are good, and it has gyro ball to hit everything hard, because the entire tier is miles faster, but primarily for Xerneus., which it can hit hard while it geomancies in my face.
Infernape @ Choice Scarf Ability: Iron Fist EVs: 252 Atk / 4 SpD / 252 Spe Adamant/Jolly Nature - Flare Blitz - Close Combat - Thunder Punch - U-turn
This one was chosen because it is my favorite pokemon. I know there are better options, but it's really fun to use, and I have a ~70 winrate with this team, so I don't feel the need to switch it out. There is a problem though. As shown, I can't decide between two natures. I'm leaning towards adamant, because it allows me to outspeed Zacian Crowned, and OHKO it with flare blitz with a min roll of 100.3. Even with rocks, jolly is only a 81.3 chance to OHKO. This nature comes at the cost of leaving me slower than a +2 Xerneus with 88 speed evs, which according to smogon's calc is what geomancy xerneus runs. My reluctance to go jolly is that I am willing to bet many people just run 252 speed on Xerneus anyways, and the power drop would be too severe.
Zekrom @ Shuca Berry Ability: Teravolt EVs: 252 HP / 252 Atk / 4 SpD Adamant Nature - Defog - Roost - Bolt Strike - Dragon Claw
Zekrom performs consistently well at taking a hit, then hitting hard. I have shuca berry to take a precipice blade, which is often all I need if Groudon is badly poisoned. Bolt strike mabye should be swapped out with Fusion Bolt for the accuracy, but I'm not sure. Mabye I should change something in the moveset, or the EVs? I'm not sure if making it faster could help with anything, or if something like volt switch is worth having. Roost helps sometimes with recovering from moves that do ~30%, because Zekrom is my switch in to physical fires, as sableye can't burn them and obviously ferro can't take anything from them.
Gliscor @ Toxic Orb Ability: Poison Heal EVs: 252 HP / 76 Atk / 88 Def / 92 SpD Impish Nature - Earthquake - Roost - Toxic - Protect
I have Gliscor as another hit taker. Toxic heal lets it take hits well and recover with protect + roost. Once again, the EVs are somewhat random. I wanted it to be kinda bulky, but still do damage, primarily to groudon. Right now, it can hit Primal Groudon for a 3 hit kill. I'm not sure if it's worth changing the EVs to better handle this. If I think they will lead Groudon, Gliscor is my choice. Usually they stealth rock turn one and I toxic. From there it is a switching game until it is dead, or they switch. Obviously not the best solution.
Genesect-Douse @ Douse Drive Ability: Download EVs: 252 SpA / 4 SpD / 252 Spe Timid Nature IVs: 0 Atk - Techno Blast - Bug Buzz - Flash Cannon - Flamethrower
I am presently torn between changing Genesect to be specs or banded. If I go specs, I would use some mixture of Techno Blast/ Bug Buzz/ Flash Cannon/ Flamethrower/ Dark Pulse/ Energy Ball/ Ice Beam/ Psychic/ and Tbolt. I guess these moves would depend on the changes made to the rest on my team members. If I go banded, I would use Extreme speed/ Iron Head/ Uturn/ Explosion. The benefits of being physical are that download boosts are easier to get, but one of the downsides is that I would struggle more against physical walls, such as Zamazenta Crowned. No matter what, I need to have either a Timid or Jolly nature, as otherwise I am slower than max speed Primal Groudon.
In conclusion, I could use some advice on set changes, and EV changes.
The Team

Mega Sableye is my team's mega, and I think it does a pretty good job. If they setup with a physical attacker, and I haven't mega'd, it can willl o wisp them. This combined with calm mind lets it win 1v1s against almost everything, especially if they are partially weakened. I regularly get this to +6 with calm mind (mabye not a great thing to do), but it takes hits well. What I would like to improve is the ev spread. It is currently just randomly set so it can be bulky both physically and specially, but I'm not sure how to change it to survive important attacks, or what those attacks are.

Ferrothorn was the last pokemon I added to the team. Full physical investment makes it an absolute wall, and it works well at forcing switches on setup mons by scaring them out with leech seed + protect. It has stealth rock because hazards are good, and it has gyro ball to hit everything hard, because the entire tier is miles faster, but primarily for Xerneus., which it can hit hard while it geomancies in my face.

This one was chosen because it is my favorite pokemon. I know there are better options, but it's really fun to use, and I have a ~70 winrate with this team, so I don't feel the need to switch it out. There is a problem though. As shown, I can't decide between two natures. I'm leaning towards adamant, because it allows me to outspeed Zacian Crowned, and OHKO it with flare blitz with a min roll of 100.3. Even with rocks, jolly is only a 81.3 chance to OHKO. This nature comes at the cost of leaving me slower than a +2 Xerneus with 88 speed evs, which according to smogon's calc is what geomancy xerneus runs. My reluctance to go jolly is that I am willing to bet many people just run 252 speed on Xerneus anyways, and the power drop would be too severe.

Zekrom performs consistently well at taking a hit, then hitting hard. I have shuca berry to take a precipice blade, which is often all I need if Groudon is badly poisoned. Bolt strike mabye should be swapped out with Fusion Bolt for the accuracy, but I'm not sure. Mabye I should change something in the moveset, or the EVs? I'm not sure if making it faster could help with anything, or if something like volt switch is worth having. Roost helps sometimes with recovering from moves that do ~30%, because Zekrom is my switch in to physical fires, as sableye can't burn them and obviously ferro can't take anything from them.

I have Gliscor as another hit taker. Toxic heal lets it take hits well and recover with protect + roost. Once again, the EVs are somewhat random. I wanted it to be kinda bulky, but still do damage, primarily to groudon. Right now, it can hit Primal Groudon for a 3 hit kill. I'm not sure if it's worth changing the EVs to better handle this. If I think they will lead Groudon, Gliscor is my choice. Usually they stealth rock turn one and I toxic. From there it is a switching game until it is dead, or they switch. Obviously not the best solution.

I am presently torn between changing Genesect to be specs or banded. If I go specs, I would use some mixture of Techno Blast/ Bug Buzz/ Flash Cannon/ Flamethrower/ Dark Pulse/ Energy Ball/ Ice Beam/ Psychic/ and Tbolt. I guess these moves would depend on the changes made to the rest on my team members. If I go banded, I would use Extreme speed/ Iron Head/ Uturn/ Explosion. The benefits of being physical are that download boosts are easier to get, but one of the downsides is that I would struggle more against physical walls, such as Zamazenta Crowned. No matter what, I need to have either a Timid or Jolly nature, as otherwise I am slower than max speed Primal Groudon.
In conclusion, I could use some advice on set changes, and EV changes.
Sableye (Sableye-Mega) @ Sablenite
Ability: Prankster
EVs: 252 HP / 120 Def / 136 SpD
Calm Nature
IVs: 0 Atk
- Dark Pulse
- Recover
- Calm Mind
- Will-O-Wisp
Ferrothorn @ Leftovers
Ability: Iron Barbs
EVs: 252 HP / 252 Def / 4 SpD
Relaxed Nature
IVs: 0 Spe
- Leech Seed
- Gyro Ball
- Protect
- Stealth Rock
Infernape @ Choice Scarf
Ability: Iron Fist
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Flare Blitz
- Close Combat
- Thunder Punch
- U-turn
Zekrom @ Shuca Berry
Ability: Teravolt
EVs: 252 HP / 252 Atk / 4 SpD
Adamant Nature
- Defog
- Roost
- Bolt Strike
- Dragon Claw
Gliscor @ Toxic Orb
Ability: Poison Heal
EVs: 252 HP / 76 Atk / 88 Def / 92 SpD
Impish Nature
- Earthquake
- Roost
- Toxic
- Protect
Genesect-Douse @ Douse Drive
Ability: Download
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Techno Blast
- Bug Buzz
- Flash Cannon
- Flamethrower
Ability: Prankster
EVs: 252 HP / 120 Def / 136 SpD
Calm Nature
IVs: 0 Atk
- Dark Pulse
- Recover
- Calm Mind
- Will-O-Wisp
Ferrothorn @ Leftovers
Ability: Iron Barbs
EVs: 252 HP / 252 Def / 4 SpD
Relaxed Nature
IVs: 0 Spe
- Leech Seed
- Gyro Ball
- Protect
- Stealth Rock
Infernape @ Choice Scarf
Ability: Iron Fist
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Flare Blitz
- Close Combat
- Thunder Punch
- U-turn
Zekrom @ Shuca Berry
Ability: Teravolt
EVs: 252 HP / 252 Atk / 4 SpD
Adamant Nature
- Defog
- Roost
- Bolt Strike
- Dragon Claw
Gliscor @ Toxic Orb
Ability: Poison Heal
EVs: 252 HP / 76 Atk / 88 Def / 92 SpD
Impish Nature
- Earthquake
- Roost
- Toxic
- Protect
Genesect-Douse @ Douse Drive
Ability: Download
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Techno Blast
- Bug Buzz
- Flash Cannon
- Flamethrower