Two sequels (namely, Final Fight 2 (1993) and Final Fight 3 (1995)) were made, but not released in the arcade. They were released directly to the Super Nintendo game console.
The working title of the game was Street Fighter '89. It was intended to be something of a sequel to the original Street Fighter (1987) and Ryu and Ken were originally planned to be the main characters.
Poison and Roxy were originally planned to be cisgender females, but were changed during development to transsexual females, only to get around the taboos of men beating up women which is controversial to North America and to feminist groups that may sue Capcom, which is revealed by Yasuda in 1993's "All About Capcom Head to Head Fighting Games". When the game was ported onto the Super Nintendo Entertainment System in 1991, Capcom USA avoided the issue all together by putting the transgendered female's natural male appearances by there birth names which are "Billy" (A.K.A. Poison) and "Sid" (A.K.A. Roxy). 23 years later, In the art book of Street Fighter X Tekken, a footnote from Yasuda states that he'll always personally view Poison and Roxy as cisgender females in Japan (which is why Poison and Roxy were in the Nintendo console/handheld versions of Final Fight in Japan).
Nintendo had very stringent censorship morals when this game hit the Super Nintendo. As Damnd's name was too close to the word "damned", his name became Thrasher. Likewise, Sodom's name became Katana (most likely because the name could be taken as a Biblical reference or because it sounds too similar to Saddam (Hussein.))