I understand your question in more of a philosophical sense. The issue that I see arising from it is due to the concept of genre. Even autobiographies have genre (e.g., historical, memoir, etc.). For example, I drew from this when I wrote in my blog about thinking of something just writing like crazy.
At this point, my major concern is that you are trying to restrict yourself to being perfect. Instead take the imperfections and just write them on paper. Once you are done after about a half hour of writing, set it to the side and come back in a couple of hours.
Notice all the ideas you had for the epilogue? Now you can start rapping up the story line.
This time you give clarity to the situation of your characters while allowing the reader to engage with their mysterious concepts.
The same principle applies with autobiography as well.
I hope that this helps.