Board Thread:General Discussion/@comment-2121812-20180917115002/@comment-1916997-20180918181535

Henry's book wasn't sucessful for one thing, so it's likely Disney didn't know about it. Even discounting that though, most of the things (Frozen and Brave stuff excluded) on Once are based on fairytales and other things in public domain, so Disney wouldn't be able to do anything anyway. Some of the names of characters are from Disney, but we could say that the book simply calls them by descriptors. Ariel could be "The Little Mermaid", Maleficent could be "The Dragon Witch", etc.