Wikipedia has Elvis predating Vim by nearly 2 years (January 1990 vs. November 1991).
While nvi isn't vi, it was intended to be "bug-for-bug compatible" with Joy's original vi. It's not quite there, but it is much closer than any of the other vi clones.
The FOSS BSD derivatives can have a vi descended from Joy's: `2bsd-vi` in FreeBSD's ports collection, `traditional-vi` in OpenBSD's ports collection, `ex` in NetBSD's pkgsrc collection. Or anyone can nab it from http://ex-vi.sf.net/ ;)
Vim is older than Elvis, by years.
The FOSS BSD derivatives never got the actual Vi editor of Bill Joy ancestry.