Do I include the Taxes and Insurance (that he's currently paying?)

What is the yearly cost of insurance?  

I currently work full time as a Insurance agent.

Beyond financing this deal, better credit will save you on insurance costs among other benefits. 

I'm thinking about putting my rental property with the same insurance company that I use for my primary residence so I can get an umbrella policy from them.

(Whithout purchasing Landloard insurance) 

These include loan payments, taxes, insurance, utilities, lawn care, and any other costs that occur during the Rehab period up until the property is fully rented. 

I will assume you have insurance against loss but the quality of the ins company can make a HUGE difference, and god forbid you need to be made whole from a catastrophe you will wish you had paid a little more for a top rated firm.

AND with an additional caveat: the PROVABLE cash flow from the property must service the debt with a cushion of at least 20 -25%, so a debt service coverage ratio of 1.2 - 1.25.That being said, the 'gap' can, in some cases, be filled by seller carrying back a second lien. 

I doubt that is enough room for taxes insurance property management (would likely be $240 on its own) vacancy, etc.