My take:
So, KoF is basically 3v3, right? Well...back in 94, you couldn't do custom teams since you had to pick one team without customizing characters in it.
This is hypothetical so don't take it as the official. Also a bit of my opinion so...it's prone to mistakes.
Let's begin. (I'll do this with a bit of explanations/references)
We'll start by basing the teams on their 94 incarnation. OPthers may follow different incarnations.
___________
Hero Team
Fighters:
(Kyo, Benimaru, Daimon)
Rank: * (Novice)
Stage: Figure-8 Circuit (Omega)
Rules/Conditions:
- Stamina Battle
- Jump Power Decreased
- Reinforcements will appear after enemy is KO'd
_______________
Fatal Fury Team
Fighters: Terry,
(Terry, Andy, Joe)
Rank: ** (Advanced)
Stage: Delfino Plaza (Omega)
Rules/Conditions:
- Stamina Battle
- Jump Power Decreased
- Reinforcements will appear after enemy is KO'd
- Lucario starts with an Ore Club
_______________
Art of Fighting Team
Fighters:
(Ryo, Robert, Takuma)
Rank: ** (Advanced)
Stage: Dracula's Castle (Omega)
Rules/Conditions:
- Stamina Battle
- Jump Power Decreased
- Reinforcements appear after enemy is KO'd
_______________
Ikari Warriors Team
Fighters:
(Heidern, Ralf, Clark)
Rank: ** (Advanced)
Stage: Distant Planet (Omega)
Rules/Conditions:
- Stamina Battle
- Jump Power Decreased
- Reinforcements appear after enemy is KO'd
- Snake favors grabs
______________
Psycho Soldier Team
Fighters:
(Athena, Kensou, Chin)
Rank: *** (Ace)
Stage: Suzaku Castle (Omega)
Rules/Conditions:
- Stamina Battle
- Jump Power Decreased
- Reinforcements appear after enemy is KO'd
- All Fighters' Magic and PSI attacks have increased power
_______________
Women Fighters Team
Fighters:
(Mai, King, Yuri)
Rank: *** (Ace)
Stage: Bridge of Eldin (Omega)
Rules/Conditions:
- Stamina Battle
- Jump Power Decreased
- Reinforcements will appear after enemy is KO'd
- Enemy melee attacks have increased power
________________
Korea Justice Team
Fighters:
(Kim, Chang, Choi)
Rank: *** (Ace)
Stage: Find Mii (Omega)
Rules/Conditions:
- Stamina Battle
- Jump Power Decreased
- Reinforcements will appear after enemy is KO'd
- Fox does not like to use specials
- Wario spawns with Chain Chomp assist
- Meta Knight favors Neutral B (Tornado)
- Meta Knight is smaller
__________________
American Sports Team (divided if I should leave them out or not, just for safety)
Fighters:
(Heavy D, Lucky Glauber, Brian Battler)
Rank: ** (Advanced)
Stage: New Donk City (Omega)
Rules/Conditions:
- Stamina Battle
- Jump Power Decreased
- Reinforcements will appear after enemy is KO'd
- Sonic spawns with Beastball
- Wario favors dash attack
____________________
After teams come the individual fighters:
_______________
Geese Howard (trust me I got quite creative with this)
Fighters:
Rank: **** (Legend)
Stage: Suzaku Castle (Omega)
Rules:
- Stamina Battle
- Jump Power is decreased
- Defeat the main fighter to win (Ganondorf)
- Cloud is invisible
- Cloud favors Neutral B (Blade Beam = Reppuken)
- Cloud favors Down B (Limit Charge or Finsihing Touch)
____________________
Rugal Bernstein
Fighter:
(Because both of their kits are similar - Up Smash resembles Genocide Cutter, Side B Wall Grab, Fireball might be his projectiles)
Rank: **** (Legend)
Stage: Halberd (Omega)
Rules:
- Timed Stamina Battle
- Jump Power is Decreased
- You have severely reduced defense
- Enemy attacks have increased power
If you want more characters for Spirits feel free to add :-)