Owl and Rabbit are the closest things you come to "intellectuals" in the books (though Eeyore thinks he qualifies as one too) and seem to be slightly more "grown up" than the others — and they're also by far the most ridiculed characters, both thinking they're on top of the game and have it all worked out, while in reality they haven't understood anything. Makes a bit more sense when you find out that these two were the only characters invented wholesale by Milne for the books — the other characters were based on Christopher Robin Milne's toy animals and were given their personalities by Christopher Robin. Of course they'd be more childlike.
It's also subtly alluded to in The House At Pooh Corner where Rabbit tells Owl that "you and I have brains, the others have fluff." It can be taken, and is probably meant, as ego stroking and praising their own level of intellect, but does gain an extra dimension when you realize that Owl and Rabbit were based on real animals instead of stuffed toys — and so they would have actual brains instead of fluff.
As I recall it, in the cartoons, Rabbit and Owl have genuine fur/feathers and no stitches, so I think Disney interpreted it that way as well.
There's a theory that Owl and Rabbit are self-deprecating portrayals of Milne and his wife, or at least how he thinks Christopher sees them: AA himself always shut in his study writing, and Mrs Milne bustling around and insisting everything has to be organised.
While the record is silent on what he thought of his mother, Christopher Robin Milne himself stated that his father was always writing, so the theory does "bear" consideration.
The Many Adventures of Winnie the Pooh ends with a conversation about doing nothing and staying friends forever. Now watch the beginning of Pooh's Grand Adventure: The Search for Christopher Robin. It's the same conversation, word for word, making the latter movie the direct sequel of the former. - Kintatsu
One teaser trailer did say that this took place where Many Adventures left off.
It also gets another callback at the very end of the movie, which also recreates the last sentences of the book and ends with:
And here we shall leave them. And here we shall find them again. For the boy and the bear will always be together in this remarkable place ... called the Hundred Acre Wood.
Winnie the Pooh And Tigger Too, which I'd seen probably a decade and a half ago. The narrator makes himself known to Tigger, and then helps him and Roo down from the tree. In other words: Tigger uses the fictional medium he's in to escape his predicament. Not only that, but since this was a movie, with the book merely as a Framing Device, said fictional medium itself was fictional. That wasn't just Painting the Medium, that was tearing it down, building up a new one, and refurbishing the whole building. -Kimiko Muffin
Also, the title is almost certainly a reference to the 19th century political slogan, "Tippecanoe and Tyler Too." That was a massive Double Take moment for me when I realized it. -fierystage
The first part of the ending credits have the stuffed animals in Christopher Robin's room "acting out" scenes from the movie. The observant viewer will notice that only Pooh, Piglet, Tigger, Eeyore, Kanga and Roo appear as stuffed animals in this section; Owl and Rabbit are for the most part absent, and when they do appear they're represented by porcelain/wooden figurines that look nothing like them. Might seem a little odd at first — but it's really a call-back to the original books and A. A. Milne. Unlike the others, Owl and Rabbit weren't originally stuffed toys.
Also at the end of the movie, Pooh and friends are seen interacting with the end credits as they scroll down. Rather funny at first, but then you realize that Pooh and friends interact with their book's sentences like this all the time, so of course, it's perfectly natural for them to interact with the credits!
Again in the 2011 film, everybody keeps treating B'loon as if it were a real character, leading to a Brick Joke towards the end. Of course, we're dealing with a bunch of stuffed animals and figurines. B'loon is no less real than any of them are.
More from the 2011 fim: Most viewers would assume that Owl was just making stuff up about what the Backson looked like, but since it's Real After All, Owl probably saw the thing at a distance and assumed that it was bad.
A minor one, but when Pooh had little to no honey on his stomach, and was depressed about it? That was not from the original books, but from Return to the Hundred Acre Wood. Specifically, "In Which Pooh Goes in Search of Honey". Very sneaky, Disney.
Near the end of Pooh's Grand Adventure, Christopher Robin explains to Pooh why he went to school. One of the reasons he gave was to learn how words are spelled, then dejectedly adds "and...how they're not." Perhaps he took an innocent word and accidentally spelled it to form something the teacher found offensive.
A bit of both Fridge Brilliance and Fridge Horror (but mostly the latter)-the reason why some of the characters act as they are is because they represent psychological illnesses: Pooh represents eating disorder, Piglet represents generalized anxiety disorder, Rabbit represents OCD, Eyeore represents major depression, Tigger represents ADHD, and Christopher Robin represents schizophrenia.
The sign (which reads "Trespassers Will") above Piglet's door. The sign appears to be broken off at the "Will" part, and according to Piglet, Trespassers Will is actually his grandfather. Do you want to know what the sign actually reads if it was shown as a whole? "Trespassers Will Be Shot!"
Could be Will Be Prosecuted, which is just a tad sad rather than horrifying.
Either way, it's entirely possible that the sign was actually there before Piglet's grandfather, and he really did call himself "Tresspassers Will". Or his uncle did ("Tresspassers after his uncle, and William after Tresspassers.")
There's an episode of the cartoon series where the group meets a giant wind-up gorilla Gary Stu. After he misunderstands Christopher Robin telling his friends he isn't keeping him (he had meant to say he was a gift for a friend), the wind-up toy goes to be in the woods by himself...and then sadly declares he needs to "unwind" and pulls out his wind-up key. He gets better when the main cast finds him and puts the key back in but we just saw a heartbroken toy commitsuicide!
"But the most wonderful thing about Tiggers is....I'M THE ONLY ONE!"...left?
He could just be bragging or boosting his ego, he is kinda immature and hyperactive after all.
In the 2011 film, various characters suggest alternatives to Eeyore's lost tail. Every time someone comes up with a (short-lived) solution, the whole gang sings a very cheerful congratulatory song. By the time they start to sing the song for Kanga, she cuts it off immediately and suggests they celebrate with silence. This of course is because she's a mother of a young child, and probably is a bit worn down by dealing with such songs all the time.