I Still Miss Dave Thomas

I'm confused by this new Wendy's ad:

Is the woman in the back seat supposed to be...

• Actually there?  The guys are really not paying as much attention as you would expect.  But they're not surprised by her presence, so I'm thinking she's an apparition, possibly some sort of "Spirit of Wendy's" which brings up the next possibility...
• The grown-up Wendy?  I guess that's possible; you'd like to believe the girl in the logo grew out of her dorky stage eventually.  But that makes the ad kind of awkward: What's next, a good-looking guy in a McDonald's ad turns out to be the reformed hamburgler?  That's why I really think she's...
• The next best thing when they couldn't afford Allison Hannigan.