For testing purposes, if you want, you can go into Facebook, select Privacy Settings. Then at the bottom, select Applications and Web Sites. In this area, you can un-approve an application. This will allow you to see the permissions popup box(es) the next time you login. If you delete the Joomla User, this will be just like a fresh registration.
Part 2 - Your dream is true. Set the "Facebook Users Only" setting, and it will do what you want. If a user clicks Login Using Facebook, they'll be automatically created an account and can revisit your site whenever. If they don't have Facebook or don't want to use it, they can click the "Register for this site" link in the JFBCLogin module and create a bog-standard Joomla account. If they log in with this Joomla account, there will still be a Facebook Connect button which lets the user 'connect' their accounts so when they return they could log in either way.
In all cases, CB will treat the user just like normal, regardless of whether they've chosen to join through Facebook, create a Joomla account, or even (later on) connect the 2.
Part 3 - No. Been told many times I look like different (famous) people, but never him. I think he's awesome, but probably doesn't know jack about Joomla
Good luck!