The Never Ending Story 2 has a different cast from what would include Jack Black. Jack Black is typically associated with his own brand of comedic acting in other projects, not this sequel. His acting style and the overall tone of his work don't really match what The Never Ending Story 2 was aiming for in terms of casting.
I'm not sure which 'fifth personality' you're referring to. If you can provide more information, I will try my best to help you find the relevant anime pictures.
There are so many possibilities for the 'Bernie Jack Black story'. It could be a story from a local community where Bernie and Jack Black interacted in some way. Maybe it's a story related to a project they worked on, or it could even be a story that started as a joke among friends and then spread. Without more details, it's really difficult to give a definite account.