For you to ask this, you're valuing that "16% CoC" so highly it's likely overriding the real material aspect of the investment.

See what's on facebook marketplace & craigslist, so many people have extra construction materials from remodels they'll give away for like $20.

Beyond that, you need to become an expert on labor and material rates in your area or get connected with someone else that is. 

The roofer gave me a invoice with high level bill of material, and a statement that it has 2 years of warranty and brand name of the shingles.It does not say brand name warranty or model or batch number etc. 

We have found that setting our expectations about what we want is helpful (financial performance, level of renovation we can handle, forced equity opportunities, number of bedrooms, etc) and then waiting for a deal to materialize. 

When you have unscheduled entry as an option, I think it encourages them to do weird stuff like hide stuff in weird spots, etc because they are always on guard.Hoarders clauses would have to be linked to fire codes I think for excess people and materials near fire sources, etc.

But we also know that the materials he employed on the Usonian houses are not exactly affordable by today's standards... 

Slowly build out a repeatable process...if you continue to change things (as in different types of properties, different levels of renovation, different finish material, different neighborhoods, etc.) you create more variables and make it harder to solve to the problem.I am a math guy and less unknowns/variables you have the easier the problem will be to solve. 

But if the blue sky materialized then repurchasing that equity could still turn into a win/win.

If I were you, I would arrange to have your materials removed before they get there to work because city guys are pretty rough on stuff they have to move.We occasionally found issues like the corner of houses built in the easement and sometimes on top of a water or sewer line.