Originally Posted by
Digifiend
She was called Prestige on the big cast splash despite having her old Bendis era Marvel Girl costume on the cover to X-Men #1. Of course, Jean has gone back to being Marvel Girl. I think using the civilian name was just a way to get around the fact she has multiple codenames. Isn't Jean the same? They both share both Marvel Girl and Phoenix, so using those two names doesn't make sense. Miles Morales usually uses his civilian name in video games for the same reason, his only codename, Spider-Man, being shared with another character.
As for the surname, well, think about it. No need to honour Jean now she's alive again. That's also why Kitty assigned her a new codename when X-Men Gold started.