So this is the team I settled on after lots of testing, but even then, I'm still unsure if I made the correct choices.
Inteleon @Scope Lens
Ability: Sniper
EVs: Sp.Atk: 252 / Sp.Def: 4 / Spe: 252
Modest Nature
-Hydro Pump
-Ice Beam
-Shadow Ball
-Focus Energy
Originally, I used a Choice Specs set, but it really wasn't good enough to make it worth using over other Specs users. After more testing around, I found this set and it gave Inteleon the power to make it work well. With Inteleon's Sniper ability pared with Scope Lens and Focus Energy makes crits always happen, it's attacks become extremely difficult to take even for the most tanky Special walls, even Blissey struggles to live most of the time.
Calculation:
252+ SpA Sniper Inteleon Hydro Pump vs 252 HP / 4 SpD Blissey on a critical hit: 333-393 (46.6 - 55%) -- 67.2% chance to 2HKO
I did have to go Modest to get into this range, but it's not a big deal, as there are only a select few pokemon that Modest Inteleon underspeeds. I also chose Shadow Ball over Dark Pulse so Inteleon doesn't get walled by Tapu Fini.
Grimmsnarl @Light Clay
Ability: Prankster
EVs: HP: 92 / Atk: 252 / Spe: 164
Adamant Nature
-Reflect
-Light Screen
-Taunt
-Spirit Break
Inteleon is too frail to live against pokemon with priority or pokemon that just outspeed it, so I wanted a screen setter. I went back and forth on Grimmsnarl and Ninetales-Alola, but settled on Grimmsnarl due to it's screens being more effective and it not summoning Hail to damage the rest of my team. Grimmsnarl is also strong enough that most opponents can't use it as set up fodder, plus it has Taunt to stop set up to begin with.
Other option(s) being considered:
Ninetales-Alola
Rilaboom @Choice Band
Ability: Grassy Surge
EVs: Atk: 252 / Sp.Def: 4 / Spe: 252
Adamant Nature
-Grassy Glide
-Wood Hammer
-Knock Off
-U-Turn
Rilaboom is here to give me some Immediate power and an option to pivot into my other pokemon. Grassy Glide is priority, Wood Hammer is the highest damage Rilaboom has got, Knock Off can remove annoying defensive items and U-Turn lets me pivot.
Other option(s) being considered:
Kartana
Dragapult
Regieleki @Heavy-Duty Boots
Ability: Transistor
EVs: Sp.Atk: 252 / Sp.Def: 4 / Spe: 252
Modest Nature
-Volt Switch
-Rapid Spin
-Ancient Power
-Electro Ball
I thought with an Inteleon and Rilaboom putting lots of pressure on Ground types, Regieleki could fit here as a fast pivot and spinner. Being the fastest pokemon to ever exist, it makes great use of Electro Ball, and I can also run Modest as Regieleki can still outspeed the rest of the meta game easily.
Other option(s) being considered:
Zapdos
Landorus-Therian
Heatran @Leftovers
Ability: Flash Fire
EVs: HP: 252 / Sp.Atk: 252 / Sp.Def: 4
Modest Nature
-Magma Storm
-Earth Power
-Taunt
-Stealth Rock
Heatran appreciates Rilaboom's Grassy Terrain weakening Earthquakes, and it helps against opposing Rilaboom trying to kill Inteleon with Grassy Glide. It also gives me Stealth Rocks which I didn't have yet.
Dragonite @Heavy-Duty Boots
Ability: Multiscale
EVs: Atk: 252 / Sp.Def: 4 / Spe: 252
Jolly Nature
-Dragon Dance
-Ice Punch
-Dual Windbeat
-Roost
Dragonite seemed like a nice addition, as screens make sure it can get off a Dragon Dance or 2. With Rilaboom's Grassy Terrain weakening Earthquake, I went with Ice Punch instead.
Other option(s) I'm considering:
Garchomp
Moltres-Galar
Dragapult
Pokepaste: https://pokepast.es/eb33800bcd45620e
