One thing I first thought about watching again is that Gaston is basically the Beast the way the Beast was at first. In that sense Gaston is a tragic figure because he probably also could change for the better.
Gaston is more of a 'real hero' than a tragic figure. To Gaston, The Beast is an ugly monster that captured the love of his life and her father. The Beast is a threat to the village and its people. Gaston is the village hero and hunter. He wants to protect the woman he loves and his community.