Piglet having a more boarlike design here was probably just supposed to be menacing, but it actually makes sense. Real life pigs can easily go feral and will grow traits like fur and tusks after only months of living in the wild.
The narrator points out that Christopher's innocence is why he was able to befriend the creatures without realising how dangerous they truly were. So a child was basically spending years of his life surrounded by dangerous wild monsters that didn't kill him simply because he brought them enough food so they didn't become too hungry. This means that if the Hundred-Acre Wood had suffered a famine earlier, Christopher might have been killed as a child.
While Owl and Rabbit's absence from the story was a result of the characters not being released to the public domain, it's possible they too were consumed by Pooh and Piglet during Christopher Robin's absence. Had Christopher not come back at all, Pooh or Piglet could have eventually resorted to eating the other and being left alone with their terrible crimes.
On saying that, Owl and Rabbit can be briefly glimpsed during an animation when Pooh and Piglet drag Christopher Robin into a cave watching from the distance, confirming they are alive during the film but never participated in Pooh and Piglet's murder spree.
Considering that Rabbits are herbivores and both bears and pigs are omnivores, it shows how stunted their animal instincts were and how bad the winter was for them to gather food. Owls and tigers are the only confirmed carnivores in their group so they likely had to be placated somehow. That being said, it also implies that Rabbit might have sacrificed Eeyore to save himself from the others because rabbits are common prey animals and he's in the company of a bear, an owl, and a tiger.
