Will Olympus lenses autofocus correctly on the Panasonic body? I'm thinking specifically of the 12-60 mm F2.8-4 zoom recently announced.

Yes. focus and aperture are those things that are guaranteed to work. Even if other features don't (Like Leica/Panasonic aperture ring on their lenses when used on Olympus cameras)

This Q&A was found on Four Thirds Cameras and Lenses : http://www.4-3system.com/modules/smartfaq/faq.php?faqid=20