About the script used to import from AddressBook.app, I update it here https://github.com/AndreaCrotti/scripts/blob/master/contacts_to_org.py
Now it creates as many contacts for the name as many as the email addresses. One thing I haven't found in fact is how to support multiple emails, is that too hard to do? Anyway in general I think I will use the VCF exported data instead, also because "contacts" is not very smart itself and a bit annoying to fetch all the single fields. A simple import mechanism (from csv for example) might be good to have directly inside org-contacts.el, what do you think?