1) Why would we classify Red as a tragic hero?
Red could be known as a tragic hero because of the long period he has stayed in Shawshank, seeing many dastard deeds happen, despite of the resources he could very easily attain. Eventually he had helped Andy escaped by fulfilling his requests for pin-up girl posters and a tiny hammer after taking a liking to the man when he was first admitted to Shawshank, even helping him in his library scheme. But ultimately Andy returns the favour by secretly stashing cash away under a rock and helping Red reunite with him at a secluded island.
2) What was Red’s flaw and how did it cause his fall from grace?
Red was facing entrapment within himself, refusing to think of life outside prison, convinced that he would not be able to adapt to the modern world like former prison librarian Brooks, who hanged himself in the halfway house. He often failed parole for claiming that prison life had rehabilitated him, which is kind of like a standard answer in trying to achieve parole, no?
3) What lessons did Red learn from his mistakes?
Andy had certainly inspired Red that life was more than seeing the dark side of prison life because even after 2 decades in prison Andy had escaped and even revealed the secret controversies of Shawshank. Andy always had hope despite the trials and tribulations and helped Red to find some in his life.
4) How did he change and how did Red change others?
Red discovered the real meaning of hope and changed his perception of prison life, and was given parole. He found the truth of life and violated his parole by leaving the halfway house and reunited with Andy, always remembering what Brooks had wrote: “I doubt they’ll kick up any fuss. Not for an old crook like me.” Red always helped others by fulfilling their requests and indirectly gave them a reason to live and for Andy, be a free man.

Actually I’m wondering why you replaced Andy’s name with Red’s? I wanted to ask questions based on Andy as he’s more the main protagonist than Red. However, the answers you gave are within reason and logical.
oh it was on andy? sarah sent me the questions haha