I think they will decide the date of the O4 and N4 Infamous 2-style. To decide the canon ending to that game, they looked to see which side more people did their first time through. The good ending won, and now we have Infamous: Second Son.
Personally, I think that if Richtofen's side is more popular, we'll play as the N4, and the O4 will be killed off, or at least not seen till the next zombies game, and vice versa if Maxis' is more popular. My reasoning is that, if Maxis' side wins, the N4 can't really escape his destruction. The O4, however, might still be on the Moon, so they would be safe from him.
Should Richtofen win, however, if he really wants to dispose of the O4, he could just turn them to ash or something. I mean, he literally has control over the entire universe and it's inhabitants.
But, I'm not really a story junkie. I don't think he hates the O4 enough to do that, and I'm not even sure if they can even escape the Earth if Maxis chooses to destroy it. I had just been thinking about the past couple of days, and it kinda makes sense, at least to me.