The names are copyrighted to 4Kids because they created them. PUSA, when taking over the license, could have bought the rights to continue use the names (because, can you imagine the uproar if they changed everyone's names?) but still credit 4Kids for inventing them.
I don’t see how that can be. I mean, wouldn’t that have created a “legal nightmare” for PUSA (now PCI), when they took over the dub. It’s just another example of Cartoon Network’s stupidity, if you ask me.