You certainly should be able to select seats. On my BOS-LAS round trip on the outbound mint was empty so we grabbed 4A and 4F (two of the throne chairs aka suites). On the return the only seat taken was one of the throne seats - 4A. I was unable to assign a throne seat to my wife first - once I picked 2A it refused to let me assign her to 2F and I had to put her in 4F. I have gone back in to try to move her from 4F to 2F and the system will not allow it. Very strange.