:I would suggest that if, say, there is a "DC Announcements Panel" and the confirmed panels are Joe Smith, Jane Doe, and John Roe, that those are the official panelists whom Marvel invited. If Summit Entertainment had a "Twilight Panel" that includes Actor Jane, Actor John, Producer John and Director Jane, that those are Summit's official panelists. 

 :That's a technical observation. Two other thoughts:  

 :Aside from things like the "Marvel Silver Age Panel," which is not organized by Marvel itself as far as I can tell, most of the panels are not so much historical or cultural as they as are promotional and commercial. How much value is there in listing the names of people brought out for primarily promotional purposes? They're essentially commercials. (A panel may be incidentally promotional, of course; for example, a panel on the history of science fiction that includes Ray Bradbury may take place while Bradbury happens to have a new book out, but that's not the purpose of convening that panel.) Secondly, this threatens to become simply a list of hundreds of names. (Let's say 20 panels a day, 5 people per panel, three days of panels, that's 300 names.) 

 :I'm not taking sides. I'm just bringing up discussion points before anyone goes to any great lengths of time and effort.