The parade is different from the toga party. They have the parade through the dining room. Many people, if not all, dress for the toga party. They will give you instructions for how to wrap the togas. In fact, some people bring crowns, sashes, and jewels to dress up their togas. Not sure about the party out of Venice, but they have it out of Port Everglades, so I would not doubt they have it out of Venice. I don't think you'll be disappointed in Costa, at least I hope not. I really, really love them!
Hope you haven't left, but if you have, Bon Voyage