Okay so this might sound like a wild theory/speculation (it actually is). Let’s get straight to the point.
Let’s see what do we know about Mother Caramel.
-She seemed somewhat famous since she saved those Elbaf pirates and ruled an orphanage. Still, no one in WCI has any clue of who she is/was.
-Big Mom created TotLand probably because of Mother Caramel’s dream.
Now, this is my wild speculation: Mother Caramel never existed in the first place, she’s a character created by Pudding so everyone could leave peacefully in TotLand.
This would explain:
-No one knows a thing about Mother Caramel. Except Pudding’s café, her café is called “Café Caramel”.
-Try reading BM’s flashback without Mother Caramel. Nothing in Big Mom’s actions/behavior would have changed. Caramel never really scolded Big Mom, just kind of excused all her actions saying she was a kind child, but she never took any active measures to control her behavior.
-Oda has introduced us a character that can mess with people’s memories. Yet no one questions a Flashback of a character that has been exposed to Pudding for years.
-If you read the flashback, Mother Caramel never mentioned to Big Mom anything about all races living together, that’s mentioned by the narrator. Plus, Big Mom seemed pretty…”innocent”, do you think she would have guessed Caramel’s intentions?
-Pudding has every reason to create “her own world”, a land where she’s not bullied anymore.
Well, next chapter might debunk this theory but I think it’s pretty funny to think that Oda could pull something like this. 
*Theory by Cintanna
Then the question would be: Who is shown on the Picture of Mother Caramel and where did it come from?
I think that mother caramel exists, because when linlin killed the bear we see caramel thinking without talking. I don’t think some character made out of puddings imagination would be able to think