The current legal status of "Winnie the Pooh" provides examples for all of this.
The original book has entered the public domain and can be reproduced, in whole or in part, by anyone. This includes the characters.
The Disney created works (books, animated, etc.) are still under copyright.
The original Pooh did not wear clothes; the Disney Pooh wears a red shirt. I could write a story based on the original Milne book and it would be legal; if I put Pooh in a red shirt, I would be violating Disney's copyright.
Many of the character names are trademarked by Disney; however, it is not a violation to use those names for new works that are not based on Disney works.
> The original Pooh did not wear clothes; the Disney Pooh wears a red shirt.
Actually, Pooh wears just such a top in chapter three, perhaps because it’s cold, and although all I can actually check at present is https://www.gutenberg.org/files/67098/67098-h/67098-h.htm#CH... which clearly shows it in the original black and white line art, I believe that it was red in colourised versions (though I’m not actually certain when colourisation happened or what its status is).
The original book has entered the public domain and can be reproduced, in whole or in part, by anyone. This includes the characters.
The Disney created works (books, animated, etc.) are still under copyright.
The original Pooh did not wear clothes; the Disney Pooh wears a red shirt. I could write a story based on the original Milne book and it would be legal; if I put Pooh in a red shirt, I would be violating Disney's copyright.
Many of the character names are trademarked by Disney; however, it is not a violation to use those names for new works that are not based on Disney works.