Every backer will receive a digital copy of the adventure module, which you will be free to copy and use as you please. Under the terms of the Open Gaming License, what's protected is more or less everything you might call fluff: the stories, the characters, the settings and the new monsters are not themselves open content, although they rely on the open content rules system to make sense. You're free to do whatever you want with the module in the privacy of your own basement.
Any person pledging $40 or more will get stats for a custom monster of my design, included in the back of their hard copy of the module. It will be creative, but not overcomplicated -- I'm aiming for that classic monster vibe.