#6 Ivory
Another notable absence in last year's Royal Rumble match was Ivory, who would go into the Hall of Fame a few months later. She returned to the ring during the Battle Royal at Evolution, where she was eliminated by Asuka.
At this year's Royal Rumble match, Ivory looks the best bet to return to the ring again as a legend, given that she didn't appear last year and her return to the ring would be more novel than that of some of the other competitors from last year's match. Seeing how she interacts with today's and tomorrow's talent would be a relatively new experience.
Ivory was as much (or more) a part of the antecedents of today's "women's revolution" as any of the legends to return last year, so her getting the nod in Phoenix would be a natural choice to spice up the Rumble match.