Lin-Manuel Miranda has promised the live-action ‘Little Mermaid’ will still feature the classic songs from the original animated movie. The 42-year-old star is working with composer Alan Menken on some new tracks for the upcoming film but he has reassured fans they won’t take the place of the likes of ‘Under the Sea’ and ‘Part of Your World’. He told Variety’s ‘Awards Circuit’ podcast: “We wrote three or four original tunes, replacing none of the ones you like. All of those are in. “There’s no bigger Little Mermaid fan than me. “But we found a couple of opportunities for some other music that …