The profiles are fixed in the SD1. You have to make your own in the SD1 menu "modify fixture". You can pick something similar and just change what's different.
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .