This is explained in the article that the original post links to. Once Winnie-the-Pooh is in the public domain, you get to use the characters as described in that book (but not, for example, Tigger, whose first appearance is in the sequel, The House at Pooh Corner, which was published in 1928). The characters from Winnie-the-Pooh, with the possible exception of Christopher Robin, don’t undergo a great deal of development throughout Milne’s œuvre, so putting Pooh as of 1926 into your own stories should be reasonably safe. Disney mostly tweaked what the characters look like, and of course you don’t get to use Disney’s Pooh graphics anytime soon, but personally I’ll take Shepard’s Pooh over Disney’s any day, thank you very much.
The thing with Sherlock Holmes was that the estate of Arthur Conan Doyle attempted to effectively get a backdoor copyright extension for the early Sherlock Holmes stuff (which is now in the public domain) by claiming copyright on the Sherlock Holmes character and arguing that the copyright term on Holmes-the-fictional-character, as opposed to Doyle’s actual stories and novels, ought to count from when the character’s development was finished (and of course the estate of Arthur Conan Doyle would be in a position to ensure that that never happened, by continuing to publish new – authorised – material that adds new facets to the character). That didn’t fly with the courts, though.
