I'm not 100% certain on this, but I am relatively sure I'm right.
Shiki and Strong World is all, 100% Oda. That's why he's getting the special treatment, because he's a 100% canon creation that he just hadn't managed to fit in to the main story- yet. I'm torn between whether his mention with Rocks is just workd building or set up for him actually having a role,
The other films aren't. He didn't come up with the stories of the characters or the film, but he did provide the designs for Z and Teseo. Bullet, however, has never had any confirmation that Oda had anything to do with him- and the studio usually does advertise it when he does. He's certainly drawn him, but I think that's the extent of his involvement with the character.