The Panopticon/Mr Men stories: novels or short stories

So we now definitively know that these stories are valid. However, the designation Dr. Twelfth (novel) really seems wrong. The definitions from T:DAB TERM are as follows:

• novel: "out-of-universe discussion about a DWU novel";
• short story: "out-of-universe articles about DWU short stories".

In other words, not helpful in this case.

But here is the standard meaning of the word "novel" from M-W: "an invented prose narrative that is usually long and complex and deals especially with human experience through a usually connected sequence of events" (boldface: Amorkuz).

To me the Mr Men stories are very clearly "short stories". They are nowhere near the length of a novel, the narrative complexity of a novel, or the minimal age for being able to comprehend of a novel.