I think the Nomad ships are written as having slums Kan. I included it in my fluff and my OCD made me check absolutely everything. If I'm wrong I must have dreamt it, which is possible.
I included a Corregidor and Bakunin slum, I imagine both to be based on run down metal hab areas.
As for the rest of the sphere, I agree, there would almost definitely be slums. It's not a perfect place although that's the image Aleph brainwash people with(#nomadatheart

).
I think the technology of bricks would be almost defunct by this stage, large engineered concrete blocks maybe but your average house brick is a clumsy approach even now. Poured concrete and prefabs would be the best bet in my opinion.