Funny story.

I originally started FFXI on Diabolos server. My name was Ryuko.

At some point many years later, I switched servers, and was able to keep my name.

Later on, I saw a guy with the name "Ryuku" or "Ryoko" or something like that.

He commented on how he used to be on that same server, but transferred away before I joined the server, and then came back after I was already there. People were constantly thinking I was him for a looong time.

With the first name/last name system, most names SHOULD NOT be taken, although if you picked a popular one (John Doe, etc), don't be surprised when you have to choose a new one.