Walkingproof, yours is an amazing story. When I read it, I immediately thought of four things, and moved from "lurking" on Websleuths to registering so I could talk with you.
First, here is an article written by a genetic biologist who made a surprising discovery when he used a direct-to-consumer DNA kit and clicked the box for "close relatives." A different wrinkle on your story, but included for your information/thought:
http://www.vox.com/2014/9/9/5975653...i-gave-my-parents-the-gift-of-divorce-23andme
Second, have you considered optioning your story to an author or film company? It would make a very interesting documentary, and you seem able to describe your situation more than well enough to fit in nicely with an author/director. If you could get a decent deal to option the story, you'd have a little seed money to continue your research, advocacy and communication efforts. In addition, the intellectual muscle and contacts provided by an author or filmmaker could help open some doors that might otherwise be closed.
Third, part of what makes your story so compelling is that it takes place where "criminal" DNA testing and direct-to-consumer DNA testing meet up. In effect, you're wanting to cross-reference from two different databases with different purposes, in order to solve your crime. I suspect there are all sorts of ethical and legal ramifications, and you're right there in the middle of it with your very reasonable request to find out whether your birth father might be proven to be your mother's rapist and possibly involved in other crimes as well.
Fourth, if you decide to pursue the book/documentary option, think high-level and don't settle. Your third cousin's mom's stepson is not the person you need. Consider Martin Scorsese, Tom Hanks, Jodie Foster, Ron Howard, Sebastian Yunger, Michael Moore. I am not sure how to get in touch with those folks or their agents but if you do get in touch with someone at that level I'm pretty sure they'd know a great story when they see it. I know some great independent filmmakers but I think you'd do best to find a big fish.
If you'd rather find a magazine or book author, long-term Websleuthians would probably know more about authors who could help you than I would. The only crime author I can think of offhand is Vincent Bugliosi.
I hope this suggestion does not hijack your thread; I know you are looking for information, not ideas that could make your life even more complicated, but wanted to share these thoughts. Good luck.