The Cirque du Soleil style performers, Kilpsinger (the descendant of Beethoven) playing the giant piano, a full jazz band, dancers, the fire works, and a crazy mc. I don't know how you could have a more over-the-top cast of entertainers, but if your budget and venue will allow for it, by all means try. There are more reasonable means of entertainment for us peasants though.
"There was music from my neighbor’s house through the summer nights. In his blue gardens men and girls came and went like moths among the whisperings and the champagne and the stars."
If you have the means to have a live band at your Great Gatsby party, make it happen. This will make your party as close to authentic as possible. It would be preferable to have a jazz band or at least a band that can play the music that you need for a Great Gatsby party. If a live band is not in the cards, create a playlist with the perfect music on it to have playing throughout the night.
Fedoras.com created this authentic playlist on Spotify of songs that could have actually been heard at a Jay Gatsby party. Play this playlist during earlier in the night and during dinner to set the mood and get people ready for dancing later.
Later on in the night (or whenever people feel like the dancing needs to start) put on the soundtrack from The Great Gatsby movie! It is the perfect blend of 20's jazz and current hip hop and alternative music; it is impossible not to dance to. This is a link to the playlist on Youtube, and some of the songs even have music videos that you could also be showing during the party.