from a insider known as Doodlepants
"While doing some digging, I got the information that it will be possible to have multiple local player sign-in in multiplayer game that support it.
What I know is that you will be able to access your information and upload your highscores."
Doodlepants has never let us down he was the first to tell us about Divx update and the 2d trophys
so I'll take his word for it.