I've been estimating Taxes as a % of After Repair Value.  

Then hit the internet websites and see if there are any recent sales to estimate current market value.

Im estimating 8 ACs and 8 furnaces and install could run about 30k.

Below are some more details with the rough numbers:12 (1 bed/1 bath unitsValue of Land:  ~$150KCost to Build:  ~$500KRent is expected to be $700-$750/unit ($8400-9000 month)Vacancy, management, expenses, CAPEX, etc:  ~$4100/monthNOI:  $4,300 to $4,900Monthly Note ($350K, 20 yr AM, 5%):  $2,309Monthly Profit:  ~ $2,000 to ~2,600Annual Profit:  ~$24K to ~31KValue of property (low end estimate on an 8% CAP:  $645K to $735K)Average CAP rate for new builds in local area is ~6% CAP. 

I'm assuming the buyer would have to include these payments into his or her cost estimate.

Don't string them out too long and squeeze blood from a stone - once you get something that works for you, make up your mind and go for it.In the end, hopefully you now have a home contracted with concessions that are significantly higher than your closing cost estimates, which can now be disbursed against your existing debts. 

(c) The licensing requirements of this Article do not apply to: (1) any person who is employed as a code enforcement official by the State of Illinois or any unit of local government, while acting within the scope of that government employment; (2) any person licensed by the State of Illinois while acting within the scope of his or her license; or (3) any person engaged by the owner or lessor of residential real property for the purpose of preparing a bid or estimate as to the work necessary or the costs associated with performing home construction, home remodeling, or home repair work on the residential real property, provided such person does not hold himself or herself out, or advertise himself or herself, as being engaged in business as a home inspector.

@Daniel Porter If you ask for a breakdown of the estimated closing costs, you will see where the money is going. 

I would definitely need to get inside the house and do a detailed repair estimate. 

That sheet looks like an estimate, not the final payment (bottom of sheet even says "mortgage estimate").Is your loan a fixed rate 30yr loan?