How do I remove duplicate contacts from Google+?
When you Circle someone in Google+, it also adds them in the "Other Contacts" in Google Contacts.

Simply de-select "Other Contacts" in the Contacts app to remove these contacts from your view.

When multiple show up (in Google's New Contact vies), deselect the person's old contact info from ANY circle. That way Google doesn't "hang on" to them, they get integrated into your existing contact for that person.