So, you need a name and not NoNameNpc or null returns everytime the pet hitting you...?
About "No name exists" on item, this will change when you first summon the pet. Then, it will show you "Name exists". If there's a name. Nothing to do with client files. Your files are ok, at least about the pets name.
I just add 3 lines at AbstractNpcInfo.java and SummonItems.java about the name. Go there, search for title, and you will get it.
But with this way, all pets(only item pets, not the pets of summoners or other class) it will show "Friendly Pet". To make the pets show names like "Wolf, Baby Wolf, Baby strider, Strider" you need to make it somehow like npcs getting name. More difficult, xml edit needed, can't explain it here..
But, another and easier way, it's to make pets getting name by their item's name(template). For example, the Wolf will get name Wolf Collar(you can change and this as well).