You're joking right? Apollonia and Vanity are most assuredly two
different people. Vanity--a Mulatto-Canadian and Apollonia--an
American-Mexican look different, sound different . . . . they are just
different!
Vanity (aka Denise Matthews) sang Nasty Girl for the group-titled
Vanity 6 album released in 1982 . Vanity left the group before serious filming
got underway on Purple Rain and Prince was forced to conduct a
"talent" search that found Apollonia Kotero, then known as Patricia
Kotero. Because the character in the movie was a singer and she REPLACED
Vanity--the girl group became known as Apollonia 6, with "Apples" as
the lead. Apollonia sang Sex Shooter for the group-titled
Apollonia 6 album released in 1984.
There is a rumor, of course, that there is a recording of Vanity somewhere
singing Sex Shooter. However, I've not heard or seen anything to
substantiate this rumor. I am almost certain that someone on this group can
confirm or deny its existence.
I would assume that you know the rest of the story about the two women, but
your question alone suggests that you do not. Does anyone else care to
continue--that is, if you even want any more information about them--?
Peace!