(no subject)
The Riku Replica does not canonly have a name, but naming characters makes it easier for us to identify/relate to them, so I don't find it hard to believe that you'd write him making up a name to use for himself.
However, "Repliku" is a moniker bestowed by fandom, and I find it hard to believe he would call himself that. He's trying to get away from being a fake, guys. That's a major part of his character.