It's a 'meh' sort of team, and I don't expect it to actually work.
Abomasnow @ Leftovers **Spruce
Impish Nature
EVs: 252 HP, 252 Def, 4 SpcDef
-Substitute
-Wood Hammer
-Blizzard
-Leech Seed/Earthquake
Gets the Snowstorm going, and eats Swampert leads for breakfast. Even with no Attack EVs, it OHKOs 280 Defense Swampert with a Wood Hammer. Also OHKOs Garchomp with Blizzard.
Frostlass @ Leftovers **Cold Heart
Timid Nature
EVs:
-Blizzard
-Shadow Ball
-Thunderbolt
-Destiny Bond
I don't really like this Pokémon, but nothing else was immune to Hail and had a Fighting Immunity. I have no clue what to use for a moveset, though.
Mamoswine @ Adherence Scarf/Choice Band **Frozen Pig
Adamant Nature
EVs: 252 Atk, 252 Spd, 4 HP
-Ice Pebble
-Earthquake
-Stone Edge
-Peck
Erm yes
Claydol @ Leftovers **Pottery
Bold Nature
EVs: 236 HP, 252 Def, Rest in SpcAtk
-Light Screen
-Stealth Rock
-Psychic
-Rapid Spin
Supports the team. No form of recovery hurts it, though. Also resistant to Fighting/Rock.
Poliwrath @ Leftovers **Amphibian (Water Absorb)
Impish Nature
EVs: 252 HP,
-Waterfall
-Hypnosis
-Brick Break
-Rock Slide
Resists Fire/Rock/Steel, and supports the team more.
Rapidash @ Leftovers ** Hot Horse (Flash Fire)
Jolly/Adamant/Hasty/Lonely Nature
EVs: 252 Speed, 252 Atk, 4 HP
-Flare Drive/Fire Blast
-Megahorn
-Double Kick
-Hypnosis/Rest/Agility
Resistant to Fire/Steel, Supports the team even more. Again, no form of recovery hurts it. This was Arcanine, but.
Yeah, rate, destroy, lock, whatever is necessary.

Abomasnow @ Leftovers **Spruce
Impish Nature
EVs: 252 HP, 252 Def, 4 SpcDef
-Substitute
-Wood Hammer
-Blizzard
-Leech Seed/Earthquake
Gets the Snowstorm going, and eats Swampert leads for breakfast. Even with no Attack EVs, it OHKOs 280 Defense Swampert with a Wood Hammer. Also OHKOs Garchomp with Blizzard.

Frostlass @ Leftovers **Cold Heart
Timid Nature
EVs:
-Blizzard
-Shadow Ball
-Thunderbolt
-Destiny Bond
I don't really like this Pokémon, but nothing else was immune to Hail and had a Fighting Immunity. I have no clue what to use for a moveset, though.

Mamoswine @ Adherence Scarf/Choice Band **Frozen Pig
Adamant Nature
EVs: 252 Atk, 252 Spd, 4 HP
-Ice Pebble
-Earthquake
-Stone Edge
-Peck
Erm yes

Claydol @ Leftovers **Pottery
Bold Nature
EVs: 236 HP, 252 Def, Rest in SpcAtk
-Light Screen
-Stealth Rock
-Psychic
-Rapid Spin
Supports the team. No form of recovery hurts it, though. Also resistant to Fighting/Rock.

Poliwrath @ Leftovers **Amphibian (Water Absorb)
Impish Nature
EVs: 252 HP,
-Waterfall
-Hypnosis
-Brick Break
-Rock Slide
Resists Fire/Rock/Steel, and supports the team more.

Rapidash @ Leftovers ** Hot Horse (Flash Fire)
Jolly/Adamant/Hasty/Lonely Nature
EVs: 252 Speed, 252 Atk, 4 HP
-Flare Drive/Fire Blast
-Megahorn
-Double Kick
-Hypnosis/Rest/Agility
Resistant to Fire/Steel, Supports the team even more. Again, no form of recovery hurts it. This was Arcanine, but.
Yeah, rate, destroy, lock, whatever is necessary.