Their little girl's name is Kaede Kurosawa. She's an elf with a thoroughly Japanese name. I really like that contrast. So Kurosawa is Shadow's real family name, and Mitomi is Holly's family name. The fact that they have a living daughter now helps hammer home the point that this is truly reality for them, and not a game like the old days.
So the players who have reappeared in the world are all players that Shin has interacted with before in the game. That explains even the existence of PKers if they're ones that Shin fought before. He was known as the Grim Reaper? Boy, he must've been real busy killing PKers then.
Interesting, so the ex-support NPCs continued development of technology that they learned from players. But what kind of detailed conversations were players having that their supports learned about bidets?