The best thing I thought about was that from the point of view of the people who were in the group last year, they really DON'T know who the new players are, nor do they know what happened to the PCs of the people that left - good role playing opportunity. Go to Comment
Surnames: The Chinese were among the very first cultures to adopt the use of hereditary surnames (around 2800 BC). But the custom didn't quite catch on in Europe - at least not until the Venetian aristocracy made it popular sometime between the 10th and 11th centuries AD. What culture made it popular in your setting and why?