Are you licensing these characters from the copyright owners? Seems like a big risk if you're not.
Some Winnie-the-Pooh material is in the public domain, so that may be okay.
I agree. Posting three examples with obvious copiright violations is a big legal risk, It doesn't mater if you draw it or the AI draw it. My sugestion is to post nice genercic drawings (like the dinosaur with the sword) and if users type "Mickey" you pretend you didn't know. (Ask a lawyer!)