Those prices are the total after me buying materials and hiring someone for labor to just hiring someone including materials and install.

Go look at the materials used, price them and add 50% of cost.

With materials and labor it cost about $3k.

All of the repair costs are estimates I've put together based on spending several hours at Lowe's and Home Depot getting material costs and using J Scott's book on Estimating Rehab Costs to ballpark the labor costs.

The time wasted with pipe dreams and how to get something for nothing you can actually learn the basics of real estate, the business, not how to move shells around for some convoluted ploy that in reality is likely never to materialize.

Of course they are very cheap I believe I did those cabinets material only for around $1,100.3.

It all depends on the material that was installed on the roof. 

I make a folder for a purchase, and keep all appropriate documents in it, Deed, HUD-1, material receipts.

o Will the developer be able to purchase building materials, bring them in, and have the labor to build while maintaining affordability?

That's a really good idea-- Off-market comps, pics of ugly similar properties, a list of materials needed to fix the problems all priced out.