Will it ever happen?
The truth is that it'll never happen. The two posters combined make just a mockery of all the Pooh's Adventures (and subsequent spin-offs) posters I have seen on the web. Every poster is just the same old movie poster but with random cartoon/anime/movie/game etc. characters slapped onto it. Lazy as heck, right? In addition, the Pooh's Adventures films break their own rules, like having the characters meet others from adult-oriented media.
Also, Pooh's Adventures has spawned countless "unrelated" spin-offs like Ash's Adventures and SpongeBob's Adventures, which are very pointless.
It's true, you heard me. This is why we tend to stick to GoGang stories instead of crossovers consisting of characters from countless media.
(Note: If you like Pooh's Adventures, please respect my opinion. The posters are also inspired by Pooh's Adventures of the Toxic Avenger (see the file OHGOGANGPROJECTSWHYYYYYYYYYYYYYYYYYYYYY.png), Maxtaro's Meatwad's Adventures of the Goodfellas, and ToxicIsland's Stan's Adventures of The Human Centipede.