She's gone on record as saying that the fairy tale is based on the Pardoner's Tale, hasn't she?

I agree with most of what you have written; pointing out the few instances of good writing really makes the rest look bad in comparision.

it becomes increasingly apparent through the book that JK Rowling views inactivity as a virtue and ambition as a sin.

Not to mention that it is Slytherin, the house of _ambition_, that is portrayed as evil throughout the series. At least she doesn't give us conflicting messages. :meh

By the way, Dumbledore was born in 1881, according to Word of God, but that revelation was probably after this was written.

At time of writing, I'm pretty sure the WoG on Dumbledore's age was "about a hundred and fifty".

Assuming he was hanging out with Grindelwald in his school days, that still puts his Nazi era more than a hundred years before the present day of the Potterverse, and a clear forty-year gap between the Grindelwald Reich and the Summer of Evil.

Very good idea about fanfiction challenges, especially with regards to chapter one. Why does JKR through Ron draw meticulous attention to how badly written the book is? I suppose because her fortune had already been made. And she does send out some massively mixed messages doesn't she? So it's OK by her to zombify your parents and friend's parents without a second thought...