Yes, it is possible. To do this go to the menu of your list "List settings " then tab "privacy". You will be able to add an “access password” to your list.

Yes, it is possible. To do this go to the menu of your list "List settings " then tab "privacy". You can hide your registry and decide at any time to make it visible.

Go to the menu of your list "settings in the list" then "Privacy" tab. You can ask not to be referenced on the search engines.