It was dedicated to Philip Seymour Hoffman, who died a week before filming ended. Since most of his scenes for the final two movies had already been filmed, the role was finished with other characters taking on his lines.
Effie Trinket (Elizabeth Banks) only appears briefly at the novel's end, but the film expands her role greatly. In the novel, Katniss's stylists are present in District 13, as well as Fulvia, who is Plutarch's (Philip Seymour Hoffman) assistant; Effie replaces these characters in the film. Reportedly, after seeing The Hunger Games: Catching Fire (2013), author Suzanne Collins called the director Francis Lawrence and said, "There's no way Effie Trinket cannot be in the Mockingjay films."
According to Liam Hemsworth, Jennifer Lawrence would purposely eat foods with garlic or tuna before any kissing scenes between them.
For Peeta to look like he was tortured, many think he went on an extreme diet. But in reality, they used CGI to slim his face and make him look abused and beaten.