You would be able to use only those elements whose copyright had expired, meaning only what’s in the original book. (See, for example, Pride and Prejudice and Z

You would be able to use only those elements whose copyright had expired, meaning only what’s in the original book. (See, for example, Pride and Prejudice and Zombies.) You wouldn’t be able to use Tigger, because that character was introduced in The House on Pooh Corner, whose copyright doesn’t expire until 2024.