It is against our Terms of Service to give out legal advice, which is what you are asking for.
I will tell you one thing, though. Creation = copyright in the United States. But when you are adding co-creators, you are likely adding complications. And look up whether you would win a court case even if you do own the copyright. Try copyright.gov for info.
Also, consider what the implications are of incomplete materials being shared. Are you so sure they won't be misinterpreted?
Some completely nonlegal advice - why not wait until you are done and share only that, preferably in pdf form, which most people can only view and not alter? Then you have a lot more control over the message and its potential alteration and spread.