The zombies would have to hire a normal human design firm to do the design and construction work.
This is no different from other non productive segments of our society who are incapable of doing things on their own.
I think of the Katrina situation where normal humans came in to clean up and rebuild; while incapable local residents sat and watched.
Actually there’s a considerable pool of talented people in the Detroit area. Most of them are retied or working in surrounding counties but they are there.
The Detroit Brothers custom cycle builders had a short lived show where they built various machines to do crazy crap. It was a rip off of Jesse James monster builder show but it was actually better. The Detroit Brothers made a point of bringing in local people for the builds. Playing the role of zombie would be a great starter job for lots of locals with few other skills.
I don’t love any city and I realize that Detroit is a favorite FR whipping boy but only a moron wants to keep a boot on the throat of any free market idea that might actually improve things.