Surprised your agent couldn't answer your questions, but the Captain's night is the 2nd night (Sunday night), which is formal. And the second formal night will be on the 6th night of the cruise (Thursday night).
While the food in the main dining room is okay (tough to feed 6000 people in 4 hours), all the specialty restaurants are very good!
__________________ Travel Agent/Cruise Specialist w/13 yrs exp and 48 Cruises on 11 cruise lines! Favorites: Paul Gauguin - Tahiti: Uniworld River Cruises - Europe; Celebrity Solstice-class ships; Holland America - 12-nights Baltics & Russia; RCCL - 14-nights Greek Isles, Turkey, & Croatia; Holland America - 14-day Alaskan cruisetour; 10-night Canada/New England cruise; 21 days Hawaii w/7-night NCL cruise; Oceania - 25 days in Asia; more than 3 months touring Europe by train. And many all-inclusive resorts!