are there warehouses ... direct window suppliers, direct flooring/doors/fixtures without home depot or someone like a Pella or Overhead Garage Door?  

If not, just disregard.If so, I don't personally have any recommendations for you on installers, but I'll share with you a few suppliers in Charlotte. 

So pay for materials direct from supplier, only paying the worker Thier wages.

Then we a deal comes along you will spot it quicker than the competition.You can continue to work on your cash reserves, your credit, your network of other investors, end buyers, suppliers and advisors.

They would have to execute a new agreement with the supplier as well as a new connection fee

You’d be surprised how often used (2-4 years old) units come up in online classifieds from a reputable supplier.

You're a merchant and no merchant can keep the doors open without knowing his product, knowing his customer and knowing the suppliers.

Get recommendations from suppliers for good, fast, quality people.

As has been, mentioned, water is the biggest enemy....And don't worry about the warranty too much, they only cover materials....so if there is an issue, the supplier will just drop off a couple squares of shingles, that's all.

His cabinet supplier should have a designer that can work with you for free.I think his electrical is about $5K too low if he is replacing all knob and tube wiring and updating panel.In regards to flooring, if you are selling the house avoid cheap flooring.