I was on this same cruise. I agree with virtually all the OP's observations and would similarly categorize the MDR food as excellent.
I would only add that the cocktail service in the casino was the worst of any of our 17 Celebrity cruises. Long waits to order and even longer waits for the drinks to arrive. They could easily have easily deployed two more servers.
By contrast, beverage service in the Oceanview was really good. We like to order cappuccinos at breakfast in the Oceanview and flagging down a server when the venue is packed (as it often was on this cruise) can be a challenge. However, this time around, I was pleased to encounter many helpful servers and prompt and efficient delivery.
Did not visit the Martini Bar.
Not sure of the specific number regarding how full the ship was, but based on the eyeball test, it was close to capacity.
All in all, a most satisfying cruise.