You have no any friends but you can search name and send friends request. Then you can put it in Google+ circle. So you can share any information just one click to circle.
you can add anybody, and you can make new circle based on your interests. i put my unknown friends to online pals circles )
I think you can add any body but need to send friend request for Access personal data. I do spend much time in Google +, still working on it.
Yeah Google + criteria is kind a different one... you can have circles there ... and your friends will show in your circles..