Sodom and Poison were originally supposed to be in Final Fight: Streetwise. Art of the pair was featured in the comic that came with pre-orders of the game, but for some reason both characters were removed before the game's release.
Cammy from the Street Fighter series makes a cameo in the game as an opponent in an optional pit fight.
Within the game, there are Final Fight arcade machines in any store that sells food. Smashing the arcade game will produce a Mike Haggar sound effect from the first Final Fight.