The New Adventures Of Winnie The Pooh is set in it's own canon while The Many Adventures of Winnie the Pooh and Winnie the Pooh (2011) are in their own canons as well.
You noticed in the TV series, they don't mention The Many Adventures of Winnie The Pooh in any shape of form. There's also Christopher Robin's American accent, when in the rest of the franchise he's British. Nasty Jack didn't know he was acting in a play.
Since he's not one of Christopher Robin's stuffed animals, he's presumably just a character Christopher Robin made up to be the villain of the play. But he only created Nasty Jack the character, not an actor playing the character. So as far as Jack knows, he's a real thief determined to trounce a real sheriff. This is why he's such a dangerous, unpredictable Knight of Cerebus. Nasty Jack did know he was acting in a play, but was too much of a Method actor.
Maybe when each of the roles were cast, Jack wanted to play the sheriff and was angry to be cast as the villain instead. He channels his envy of Piglet into the nastiness of his performance. This also explains why he does a Heel–Face Turn when Piglet makes him the new sheriff in the end – this unscripted, improvised twist satisfies his ego. The show will be revived one day.
But it would be a lower budget. The show was supposed to premiere in 1987.
It’s unusual for a TV show to start broadcasting during the former half of a year unless it’s been delayed. For example, Ed, Edd n Eddy was supposed to begin between September and October of 1998, but instead began in January 1999.According to a newspaper article from November 1987, the first thirteen episodes were completed at this time. It’s not too far-fetched that the show was about to start that same year, but they didn’t want to clash with DuckTales (1987).
Kessie was a real bird that Christopher Robin rescued.
If we assume the whole series (and the whole Winnie the Pooh canon) takes place in Christopher Robin's imagination as he plays with his toys, then this would explain the plot of "Find Her, Keep Her." Christopher Robin found an orphaned baby bird and cared for her until she was strong enough to fly away. He wanted to keep her as a pet, but ultimately he had to set her free. Since young children often deflect their own heavy emotions onto imaginary friends or toys, Christopher Robin dealt with his own sadness by making up the story of Rabbit raising Kessie and not wanting to let her fly. There are other Tiggers living.
They're just in hiding, like all those do-dos who turn up at the end of Porky in Wackyland.