Why wouldn't you invite Deadpool? He is the life of the party. He is hilarious. He is a great dancer. He will indulge in my chimichangas.
2. Iron Man
Tony can provide the place and the music systems. He also lives the party life.
He saves you, you give him fun. Also, he could help you pick up the ladies.
4. Green Lantern
All human GLs are partiers. They can help decorate. And Guy is an experienced bartender.
The Main Man would have crashed my party anyway.