Nice paper. I just want to point out that comparing the occurrence of last names against those in the general population will find out a greater occurrence of same-name even in non-nepotistic systems, as there is an important bias: the proportion of children having the same job as their parents is greater than the proportion of people having that job in the general population, even because of emulation and socio-economic background alone.
Comparing the occurrence of last names in academics against those in professional organisations (e.g. Ordine dei Medici Chirurghi e Odontoiatri) could avoid this bias.