Based on that it would be 3 stages. The Arena, which is a large size area which was the main stage, the Thomas Wolfe auditorium (which connects to the arena and can be reached by indoor ramps and hallways), and the exposition area which I believe was the area underneath that they used last year to check in people's tickets, search them, etc. They are all inter connected. Last year they used tons of venues around the city for the event including the art gallery (for Brian eno's artwork), the movie theater (for live scores to movies) and various other bars, venues, auditoriums and theaters around the city and a large outdoor stage in a parking lot. It was very cool and fun walking around. I guess they wanted to localize it more. I can only assume that the other venues will either close, have separately ticketed events or something during this. I can't imagine they would shut down completely for 3 days.
As for the Thursday event I am assuming it is some act or acts that will play the Arena on Thursday. The only thing I can think is either Peter Gabriel, ELP (they said they tried to book them last year but couldn't) or David Byrne. I am just not sure