What are you saying? That article says exactly what I just said, and I quote the article: "Nero IS Vergil's son, and that this aspect was going to be implemented in to the game's plot. However, the decision was made not to, which could set up a good story for the future." Though first time I am hearing that they even had that idea at all. To be honest, I'm glad they took it out.
I've never heard of this before prior to your link, it might make sense seeing how in game Nero is compatible with Vergil's power through Vergil's sword Yamato. There is no hint of that in game, though it might be interesting to see if they do something with that down the road.
HAHA!Well Trish was created by Demon's to look like Dante's mother, so she is a demon- or something else is still unknown. So she might not be aging at all. Dante and Vergil are twins so of course they are the same age, and you can see that Dante looks the oldest in DMC4 so he is getting up there. I'd say he is probably in his mid-30's, and Nero is probably like 17-22 somewhere