I suppose not, though Lazharis would know as much as Vasile. I mostly didn't want it to feel like the NPCs were just dragging you along for the ride.
For the record, Lazharis and Vasile are part of a different Unbroken Cell, which will make contacting the others more difficult than just walking up and knocking on a door.
There are three key places you can start looking:
The Cathedral Ruins. While the ruins themselves are officially off limits, and there is the ever possible threat of whatever destroyed the temple in the first place, many still sneak inside to pray or hold clandestine meetings. The locals turn a blind eye to the trespassing out of sympathy.
The Vice Houses, a Bordello/Casino/Bar mostly frequented by conscripts (who are not affiliated with the secret police a.k.a. Rats)
The Arena, a repurposed outdoors amphitheater that is being used by Houses Ghallanda and Jorrasco as a soup kitchen and field hospital.
And for the purposes of finding people in a city, Investigation would be a go-to skill.