^This is actually the same speculative conclusion i came to, and some of her poetry brought me to it as well. So Many Fools comes to mind..
I think she really did mean it when she said this book told the whole truth, thing is, you need to know about her actual history in order to see it.
That was the conclusion I came to. I took the whole Emil-y thing as an allegory for Emilie's life, especially the things she didn't want to admit or face. She fictionalized them and set them in a far away place to deal with them better. This was also how I was able to accept the historical inaccuracies, like Suffer for stuffed teddy bears weren't invented for a good 50 years after the story is set.