In general the most common names in Catalonia are Montserrat and Jordi, the Patron Saint's of Catalonia, but if you look it up on internet during the last years names as Març, Laia or Àlex are on the top of the list.
My name is Lucy and sometimes people make reference to one Bittle's song or movie
My first name family is more common in the south of Catalonia, the second one is Princep, and in my village all the people with this name belong to the same family. Also in most villages of the south of Catalonia, the families have a nickname and everyboby knows it , nowadays is a tradition that we are loosing.
Another curious thing is that some people who watch soap operas on the TV, name their soons with tne name of the main actor or actress.
The use of the first name or the family name depends on the situation, for instance, if you are in a formal conversation and you have to be polite you probably use the name and the family name to introduce someone.
About the use of pet names, I think sometimes people use them in public and some of these names are very ridiculous.