Steven Zahm@ Heather
1. Sorry, no, there is not an all-in-one solution for creating families. The best suggestion I can give is to use the CSV Import extension to import the individuals all at once. Then the only step, would be to create the families.
2. I suggest making the entries private. Private entries will only be visible to users that are logged in. Depending on your role setup and the role your users have, you may have to go to the Connections : Roles admin page and give that role the view private capability. You can then uncheck the private override option.
3. I suggest enabling the require login option under the general tab. You can then use any freely available login form plugin that has a shortcode to add a login form to the login required message.
I hope that helps!