If you aren’t sure of how to price things out you can meet with some contractors and suppliers and create price lists and build your cost database.I always plan for a 5-10% contingency depending on the cost and scope. 

Everyone would just ask their supplier to break out every invoice into line items that don't exceed $2500. 

They are already in the market where you will be investing and know it well and have experience dealing with all the people you'll need, such as contractors, city govt, laborers, building and zoning, material suppliers, etc. 

Do you have great relationships with any suppliers?

I am looking to find cabinet and granite countertop suppliers who are investor-friendly.

It was the same granite Home Depot had, we just found their supplier and saved quite a bit. 

However, it does not provide for any holdbacks/retainage from each payment.I have heard construction lenders will hold back from each draw.Even though I am paying in cash, should I not require some sort of holdback (5%) from each draw to protect myself from incomplete work and unpaid subcontractors/suppliers?

from each draw to protect myself from incomplete work and unpaid subcontractors/suppliers?

from each draw to protect myself from incomplete work and unpaid subcontractors/suppliers?

Some states/energy suppliers have additional rebates.