Yes, they do pipe in the music, but it's still hard to hear because the restaurant has wood floors and high ceilings. Kitchen and diner noise drown out Wishes. Ask your server if you can hear the music outside the restaurant. That could be an option for viewing Wishes. The view is killer, so I hope you get a chance to hear the music, too.
Your PS time depends on what time Wishes will be that night. If it's 9 PM, I would make my PS for 8:30. If it's 10 PM, then I would make the PS for 9:30.
I highly recommend the salmon! I am a big fan of AP's Cedar Plank Salmon, and this one is different, but better, IMO.