If you have a communal iPad or other device on which you will use FaceTime, and you have a number of users who are old enough and mature enough to need their own contact lists, you can set up multiple FaceTime accounts. This way, a user can login as themselves and only see what they need to see. I am mainly talking about contacts, call history and favorites. For example, when I set up the FaceTime account for my mother-in-law, it only has two contacts – her daughters – since that is all she needs. She gets on FaceTime and goes to favorites (or contacts since she only has two) and sees exactly who she needs to see.
Note: Keep in mind that First Name, Last Name and Email address are all publicly searchable.