It’s easy to explain how it might be possible for Pinocchio to grow up, though.
Gepetto could have helped him escape when he built the magic wardrobe in an effort to protect his son. Therefore Pinocchio grew up in our world unaffected by the curse. But since he was connected to the people there- as with Emma- he was able to enter Storybrooke.
They made a point to tell us early on that Gepetto in Storybrooke has no children. I think if Pinocchio existed in Storybrooke as an inanimate object or a child in school, we would have seen him by now.
August knows too much to be a character who was not close to the central characters when the curse was enacted.
August as Bae would require many random twists to make possible…how did he get to our world? How would he know about Emma? What about the fact that the writers said Rumple became the Dark One centuries earlier? I will be very surprised if they go that route….it would require some serious manipulation of events.