There isn't usually a difference between sea view vs.ocean view, but there can be a difference between ocean view and water view. This can occur in places that are close to the ocean but also have other bodies of water, such as a bay, lake, or river.
Generally, Deluxe means full ocean view, versus partial. If you are booking through the Ilikai Hotel site, you can see the descriptions there. In my experience - deluxe has meant a higher floor - more expansive view. Often quieter.
Whether you choose an oceanview or balcony cabin should come down to two primary considerations: price and itinerary. Can you afford the extra money you'll pay for a balcony? Or, even if you can afford it, would you prefer to spend that extra money on some other cruise experience (drinks, shore excursions, the spa)?