Allowing guests to post & some questions.

[DISLEX]

I created a section on my forum where users do NOT have to register. Anyone can come and post.

01. When someone clicks to make a new thread, it asks "Your Username:" and let's them type something in. How can I make it so that they are something like 'Anonymous###' or 'Guest###', or something to that affect?

02. When someone clicks to make a new thread, it asks them for the CAPTCHA verification I have for when people register. How can I make it so they ONLY have to use the other spam prevention I have setup. It's the question type. "If A=1 and C=3, what does B=?"

03. IF, I did decide to let them pick a username each time they create a thread, how can I prevent such names as "Admin", "Mod", etc...?

Thank you.