I've written several short stories that I want to expand into a series of books, and an idea came to me. I was thinking of the books by Og Mandino. They all had a message, but they were all very short books. I'm guessing most of his books were only 50,000 words tops; they certainly were not normal novel length.
Would that work in today's world? Is it even possible to find a market for novellas? If I wrote this series of books about special children named Hope, Mercy, and Peace, and they were all in the 50,000 word range, would I have any chance of finding an interested publisher?
I had to look up Og Mandino because I knew the name but couldn't have told you a thing about his titles (that's a clue right there.)
Turns out Mr. Mandino isn't writing novellas at all. He's writing self-help and inspiration. He may be using story form to do it (Simon the Ragpicker etc.) but his goal is to is to teach, not entertain.
If that's what you want to do, and it sounds like you do if you've got "special children named Hope, Mercy, and Peace" then it's not the size of the book that's the problem it's the style.
You need to figure out what you're writing. If it's self-help and motivational essays, then it's NOT a novella. If you want to write a novella, make sure you're telling a story first, not trying to teach a lesson. Books with heavy handed overt messages are non-starters these days no matter their length.