1) Check out this module in the gallery:
I've never used it but should suit your needs fine. You will need to create a
and attach this to the User content type.
2) The link you mentioned would be the correct way to do it. You should be able to do:
Then assign roles as described in the blog.
3) Check out the rules module and the Email messaging module, you should be able to create a rule to do this
But as Sebastien says, there is a new Workflow module coming out soon, which will help you achieve some of what you want. And I believe Rules is to be deprecated so you may want to avoid using that and wait for Orchard 1.7 :)