[u][b][i]Regarding Same Time Arrival[/i][/b]
[/u]
Everyone arriving at once isn't that important, but more to not have plot holes. Like if the characters arrived before hand, they would have a lot of info on the City which would make the "exploration" aspect rather less fun since they'd know a lot more than everyone else. It's also to keep everyone sorta on the same playing field at least at first, since there's going to be a Contribution System in place that allows the various characters to earn points that lets them spend it on stuff they can bring over from their home dimension or other universes so long as it's something they know how to handle like guns for soldiers or magical equipment for mages and so on. 

[@VitaVitaAR] Yeah, I'll keep that in mind, eheh.