copy production to sandbox

I'm about to make a copy of our production instance and copy over our existing sandbox instance. I understand that when I do this it will automatically go into administration mode.

Just a couple of questions.

1) Will all current production users get access to the sandbox as I will be copying their user records over? I don't want them to have access to sandbox unless I need them to get involved in testing.

2) I don't want emails to be tracked into both systems. Is it advisable just to turn off email settings in sandbox?

3) What other settings should be different in sandbox to production. i.e. I plan to turn auditing off in sandbox. 

4) Presumably when the copy is made, the url is different so existing connections to production using web services will not be affected?

Many thanks

James