I like this color combo (sea green over navy blue) over dark denim, sweater needs the heathered knit, not solid if wearing a non traditional color. J Crew style, sea green cotton sweatshirt worn over blue checked shirt with denim.
Because you’re going to be dancing for most of your dress-up time, you’ll be pairing blazers and jeans a lot. For that, you’ll want more casual blazers. Also, the sweater pairing is sharp, though probably too warm for the dance floor.
Team a brown checkered sportcoat with charcoal jeans for a seriously stylish look along with Charcoal Jeans — Brown Plaid Blazer — Mustard Crew-neck Sweater — Black and White Polka Dot Pocket Square — White Longsleeve Shirt