No. As a territory of the United States you do not need a passport to visit Puerto Rico.

Beach cocktail attire is semi-formal beach wedding attire. Men's ties are optional, but still welcome. If you're shopping for menswear, start with a classic long-sleeve button-down and dressy pants; then, add a colorful blazer or patterned sport coat for festivity if you would like. Appropriate footwear includes nice loafers and on-theme boat shoes. Women can wear a semi-formal dress, like a maxi or midi, as well as a jumpsuit or dressy separates. A beach cocktail dress code gives you the flexibility to choose a vibrant color or bold print. Finish your outfit with a low heel, wedge or dressy flats. Beachy accessories, like a raffia clutch, are also acceptable.

Unfortunately, no. The required number of rooms to reserve a block with the resort was higher than we expect to have at the wedding.

“According to Kyle Potter, executive editor at travel and flight deal website Thrifty Traveler, the ideal window for booking domestic flights begins at least a month in advance. Senior product operations specialist Willis Orlando from Scott’s Cheap Flights suggests booking domestic flights for a destination wedding between one and three months in advance. Generally, you don’t want to leave your flight booking until the last minute, hence the advice to start looking no later than one month in advance. But airfare varies based on a number of factors, so it’s always worth checking the cost of your flight a number of weeks in advance and monitoring the cost to ensure you’re not paying too much.” - - https://www.cnn.com/cnn-underscored/travel/best-time-book-wedding-destination-flights