Cooper was not a lock for a nomination. In many circles the other four nominees were locks, and the fifth slot could have gone to any number of actors who gave good performances. Have you seen Mr. Turner or Selma for instance? Sniper with 6 nods including Picture, Actor and Screenplay came as a bit of a jolt.
Cooper will attend not because he's going to win (Put your money on Keaton), but because it is good politics to be there.
As for Curious Dog (as I seem to end up calling it), it is selling very well and like any show, weekends will go first, so get cracking. What others have said is true, mezzanine is preferable over orchestra. If it is sold out already, look at Disgraced which packs a wallop. The Audience is pretty good too.
When Ellen Burstyn won 40 years ago, there wasn't the pressure to get the nominees to the awards like there is today. There always seemed to be at least one winner who wasn't there.
"If my life weren't funny, it would just be true. And that would be unacceptable."
--Carrie Fisher