Be fair, Mundus owned the not just the city but the whole world, that does kinda limit your options of where to hide
Managing to hide from a god, right under his nose, for any amount of time, would suggest a certain degree of competence?
For some reason I always figured that Limbo city was a testing ground to test his control over the humans until he expanded his empire.
The comic has them giving out a new improved brand of Virility drink to the public and this wasn't too long before the start of the game.
Plus that news article in the game says that Mundus only came to be head of finances a week before the start of the game. So it's only recently that he has aquired so much power by forcing the President to give him that position. However, the article also states that Raptor news had been active prior to that.
I guess what I'm trying to say is that when he tracked down Sparda, Eva and the twins, he didn't have the same kind of power, so they should have been harder to find, but he got them anyway.
Lilith says Mundus used hunters to find them. Would they be like the same hunter that came after Dante?
Something else that bugs me: It is shown in that art of Mundus taking out Eva's heart that he is in Kyle Ryder's body, so what was he doing that whole time between killing Eva and then being head of Silver Sacks a week before the start of the game? That's what....over 10 years to take over the world, but it seems like he's only just done it fully by the start of the game after he bullies the President.
Eva does sound genuinely surprised that they were discovered, which would suggest that they should be safe from detection. How? Help from the Angels? Were they betrayed? By who? Why? What part did Sparda play in Mundas' rise to power? Does Virgil have the full picture, remember its the winning side that writes history? etc etc
I bet she would be surprised, bunch of demons turning up at night and raiding the house. Sounds like Sparda was there too from the way she was calling to him. So why did he let his wife die like that and in front of his son? And how did Sparda escape the house with the twins without being found? Did Eva give her life as a distraction?
It seemed like Sparda and Eva's plan was to just live like normal humans and hope that they weren't found out. Eva says to Dante that they chose their path knowing that they would die eventually. She new that they could not hide forever.
As for how Vergil knew, he says that their old home showed him his answers and secrets. That's how he explains it.
There is more than enough there to spin into an interesting tale, should they want to.