Ugh, stupid nitpicks irritate me.
"No one can tell this little girl is different from before"? Oh yes, then it must mean she had a never-before-performed brain transplant! Why would anyone jump to such a conclusion? Kids do random shit all the time. The mother was an actress, she had roughly ten years of preparation, and we were even shown that she had studied and documented her daughter's schedule, behavior, and habits. Despite all that, there actually *was* a character who grew suspicious, and we saw what happened there.
"...just an actress...somehow became a master manipulator"? Because that's mutually exclusive to being an actress? Oh, you must assume actresses are stupid or something, since she's "just" an actress? You realize a key to being a good actor is getting inside the head of someone else to play a part? Figuring out how they'd react to various situations? She's not doing anything terribly sophisticated, either, just observing, predicting obvious reactions, preparing simple traps for those expected behaviors, and acting the part of a helpful and earnest little girl to dissuade outside suspicion.
"...no adult can overpower her"? Who's trying? One scene this happened, and considering all the factors at play it makes sense. We're talking about a petite Japanese woman who recently gave birth, is in an unstable state of mind and about to commit something she would ordinarily never do, and the girl surprises her with a trap and then makes her hesitate with the threat of being caught in the act. Although the woman is physically stronger, her fear-paralyzed will wasn't applying it, and the girl who had clear conviction used everything she had with purpose and efficiency. If you are not standing firm, even a kid can push you off balance. Once on your back, tangled up, you can't apply nearly as much strength because you've lost the leverage of your body weight.
Ha, thanks. Forgot to add my normal handle. Oh well!

It's really hard to take this seriously... this lady was just an actress and somehow became a master manipulator? No one can tell this little girl is off/different from before? Most of all, no adult can overpower her??? Also I laughed when the mom tossed the baby on the ground lol.