After the attempt where I checked the box that allowed for duplicates, the import was Completed without failure.
However...
1. The contact is not in the list.
2. The contact name was not in the list before either, so I don't understand why allowing duplicate records allowed the import to be completed.
3. (more of a side question to the above two points) The one field that I was alerted is not mapping is 'Full Name' - is this automatically calculated using 'First' and 'Last' names?
thank you very much.