Ну а дальше-то Шапочка начинает “отсебятину плести”: - Иду к бабушке и несу ей пирожок и горшочек масла и т.п. и т.д. Чем это принципиально отличается от того, как Пуаро с Гастингсом у той же Агаты Кристи “воркуют”?
First person narration is the narration by a person who has participated in the story him/herself.
Third person narration is the narration by a person who does not participate in the narrated story.
In the both ways of narration the narrator can recite what other characters said (or thought) it is called direct speech.

In the case of the "Little Red Riding Hood" it is neither the young girl nor the big bad wolf who tells us the story, even though there is direct speech of the both of them in the story. It is somebody else who was secretly running behind the red riding hood and listened and scripted everything she and the big bad wolf said. It is called the third person narration.

While in the "Hercules Poirot" stories it is Hustings who tells us the story. And he refers to himself as "I" in all the parts of the text outside of direct speech quotations. This is called the first person narration.

Я так, честно говоря, и не понял (если опуститься с высот метафор и сравнений на грешную землю), в чем заключаются трудности письма от имени женщин:
-В загадочной женской душе, ее иррациональности и непостижимости?
-Ограниченности мужской способности к эмпатии и воспроизведению чужого “потока сознания?
-В том что это просто нехорошо, и “настоящие мужики ни за что на свете такими делами заниматься не станут?
-Никому такое чтиво не интересно?
-Стилистические трудности?
-Что-то другое?
Let's imagine that you have two friends, a man and a women, who have watched a movie you did not. You ask them to describe the movie for you two decide whether you want to watch it or not. But currently they are unable to see you in person but are ready to send their descriptions by e-mail. I bet you find out which description is written by whom even if you will not look at the sender's e-mail address. So if a male author want to write a story as if it was written by a women he probably would need to put some efforts to do it a little bit different with respect to his general writing practice.
I don't know would these efforts be big or small I never tried it myself.

Ну и в чем заключаются "mixed fillings"? Что там так не понравилось?
I didn't say I didn't like it. I just said it was unexpected and I was curious how frequently male authors do it this way.