Unused sprites
Looks like you could choose your first CPU opponent originally, similar to a lot of Neo Geo fighting games available at the time.
The arcade version of Street Fighter Alpha 2 doesn't have a survival mode, although clearly it looks like one was planned at one point.
An alternate version of the above. Whilst this isn't used in this version, it would be used in Street Fighter Zero 2 Alpha as there's a hidden survival mode available.
It looks like originally, if two players started a game, you were supposed to get a choice where you could choose the above...
...or your could choose dramatic battle mode! Dramatic battle got cut from this version, but was included as a secret mode in Street Fighter Zero 2 Alpha.
Unused player 1 and 2 indicators that possibly related to the cut dramatic battle mode. I couldn't find any palettes that made these look good.
A couple more sprites which clearly relate to the above. Again, I couldn't find any good palettes for these.