Cabin: D021 ;Our cabin size was good, but you will want to stay on the other side of the ship if you want to see the ports upon entry. This was not a big deal to us since my husband is into photography and took pictures up on deck anyway. If you get sea-sick you will want to stay on this floor because the rocking is decreased. We were right outside the elevators, but did not hear any loud noises or noise that woke us up. Very good insulation from noise.
Food: We did breakfast at the buffet each day and lunch and dinner at Anderson's (sit down style and included in price). We choose to have lunches at a table for 2, but did dinners at group tables. We only had 1 bad dinner group (very quiet and negative bunch). Otherwise, we met amazing people and had a good time. We did not eat at the addt'l cost restaurant based upon reviews and fellow travelers. General consensus was it was not worth the up-charge.
Havana: The best of the ports by far. Make the most of your time by staying out late during your 1-night stopover. Head over to the Malecon at night, go to a local restaurant (or 2) for drinks and snacks. You're only here 1 night and it's the most "immersive" experience of the whole trip. We did not pay for the extra excursions. People said Tropicana was amazing, but I already know that Vegas style shows are not for me. If you like them, then go. It sounds like you'll love it. Don't do the "old-car" excursion through Fathom. You'll save half the cost with the guys right outside the customs house. Some people did private tours on Day 1 (after the Fathom walking tour) and they all had great things to say. I wish I would have thought to plan for that.