Please don't do this thing. You have taken a single passage out of copyright law and are trying to use it as a perfect shield. First, consider that IP law gives tax law a run for its money in terms of complexity (or is it the other way around?). A single passage will not save you, should WotC decide to sue.
A couple of significant, specific points:
1. Giving it away for free. Doesn't impact the legality one iota. This is not even relevant to the discussion. Please don't bring it up again.
2. Taking your name off. Again, doesn't impact the legality. As someone else pointed out, should your publication be found illegal, this would be the equivalent of wearing a mask. The most likely impact is that it would negatively impact any penalties against you, should you be found guilty. But, for purposes of determining if this is legal or not, it doesn't matter at all.
3. Improving the game/industry. Just because you think you're doing the game a favor doesn't give you the legal right to publish. If what you are doing impacts WotC IP, they have every legal right to mismanage their IP into the ground. Don't use your intent to muddy the waters.
You have demonstrated an appalling bad grasp of even some rather basic legal principles. You don't even seem to have a grasp of the difference between the SRD and the OGL. If you move forward with this project the way you seem hell-bent to do, your hope of avoiding procecution lies not in any legal high ground, but in pure obscurity. In other words, the best thing that could happen to this project is that no one ever looks at your document.
Your interpretation of what constitutes "uncopyrightable" mechanics is way off base. You can pretty much use "you gather as a group, build characters, and roll dice to resolve tasks". You could probably get away with rolling a d20 for most resolutions. When you start getting a list of classes that mirror the D&D classes in function, if not in specifics, you running into a copyrighted expression of the work. The fighter class is IP and just renaming it doesn't change that.
Putting the material in the SRD does not put it into the public domain. Quite the opposite, really. The terms of the OGL allow WotC to explicitly retain ownership of the IP. What it does is allow others to use that IP in a standardized manner without being a threat to WotC's ownership of it. If you use that IP in a manner inconsistant with the license (OGL = Open Gaming License), it is a violation of that agreement and becomes a threat to WotC's IP.
Now, WotC did not have to create the OGL and SRD. It actually cost them quite a bit of money to do so. It already spells out a nice, safe way for you to use their IP. It seems disrespectful to work rather hard to circumvent that license, especially considering you get nothing out of it.
Your stated reason for not wanting to use it is that you don't want to advertise for WotC. Help me understand how you could enjoy the game so much that you want to release a suppliment for it, but do not want to prompt anyone to purchase it. I assume I missed something there because that seems a bit counter productive.
