Manage the ability of unregistered users to comment sitewide, across the entire network.
No, this is completely separate.
If you set comments to be spammed or moderated, they will show up in the appropriate section of your comments page. If you set comments to be blackholed, no one will ever see them. Ever.
No, it only blocks by email address.
I don't find it useful, and I think WP's the wrong tool. If you're blocking IPs, given how dynamic they are, it won't do you any good in the long run.
Yes. If you put 'example.com' in your list, it will block 'firstname.lastname@example.org'. Be very careful when you do this! If you put in just the letter 'a' for example, you will block all email addresses with that letter. Please only use full domains ('example.com', not just 'example').
This plugin will not block any logged in user, even if their email is on the list. If you don't want them commenting, delete their accounts. It's assumed if you let someone on your site, you mean for them to have access.
Yes, it does.
No, and what's the point? You already have a blacklist for that.
I don't know. Let me know!