Not gonna be on the Wonders of Life side. The new restaurant will be built between Mission: Space and Test Track, possibly utilizing the old, unused VIP lounge building that was originally built when M:S was built but never used. And the restaurant will more than likely be closer to the main promenade.
This may have already been said, but I think the menu doesn't need to be quirky or overly themed with "space"-sounding items. It could literally just be billed as a fine dining restaurant in space. Steaks, seafood, etc. ...with one heck of a view! Just like real orbiting space resort restaurants will be in the future, of course.