@Andrew Briggs We collect all court records 2 times a day and store historical recordsScrub all data against property ownership.Run vacancy status on all houses in countyPull all delinquent taxes in countyrelate all property ownership - who owns what properties and how manyPull Corporate structure on all LLC's - Get contact name for company...And output this file daily with our sell score. 

The building had historic designation, meaning the new roof costs $1,000,000.

From beginning to end and a way to track historical data.

One-time Expenses$1000 - Acquisition Costs (minor rehab, legal, & inspection)Annualized Expenses10% Gross Annual Rent - Vacancy Costs (turnover & lost rent)10% Gross Annual Rent - Property Mgmt (standard)$1176 - Repairs & CapEx ($1 per sq foot for tpical property)$1516.46 - Property Taxes (5 year historical average for typical property + 10%)$1000 - Property Insurance (a nice round number: seller reported that he paid $708/mo for one duplex)$27 - Water & Sewer (average across several properties from last month)$0 - Gas, Electric, HOA, Snow Removal (tenant pays or not applicable)$60 - Lawn Care (I made this number up)COMPARATIVE ANALYSIS:This is my analysis of the five properties that are being negotiated right now, listed from best to worst.Property Alpha (two-flat)$1250 - Income, Monthly (actual)$567.37 - Expenses, Monthly (estimated)$42,000 - Price, Signed Contract36% - Cap Rate (Annualized Income / Price)16.6% - ROI, After Tax (annually, assuming 15% income tax)6.0 Yrs - Until this property pays itself offProperty Bravo (two-flat)$1100 - Income, Monthly (actual)$537.37 - Expenses, Monthly (estimated)$42,500 - Price, Signed Contract31% - Cap Rate (Annualized Income / Price)13.1% - ROI, After Tax (annually, assuming 15% income tax)7.6 Yrs - Until this property pays itself offProperty Charlie (duplex)$1075 - Income, Monthly (actual)$532.37 - Expenses, Monthly (estimated)$55,000 - Price, Informal Discussion23% - Cap Rate (Annualized Income / Price)10.7% - ROI, After Tax (annually, assuming 15% income tax)10.3 Yrs - Until this property pays itself offProperty Delta (SFR)$875 - Income, Monthly (actual)$492.37 - Expenses, Monthly (estimated)$48,000 - Price, Informal Discussion22% - Cap Rate (Annualized Income / Price)8.8% - ROI, After Tax (annually, assuming 15% income tax)13.6 Yrs - Until this property pays itself offProperty Echo (SFR)$770 - Income, Monthly (actual)$471.37 - Expenses, Monthly (estimated)$62,500 - Price, Informal Discussion15% - Cap Rate (Annualized Income / Price)4.1% - ROI, After Tax (annually, assuming 15% income tax)24.4 Yrs - Until this property pays itself offNotice how the price keeps going up?

Historically, the entire cycle takes about 19 years on average.

Even if the lead has a proven track record I still have no way of evaluating that persons historical moral code. 

Unless you want to generate history for which unit is historically easier to rent, or has a better return. 

Unfortunately - for lack of historical perspective - since LLCs shave been around, interest rates have been going down; if this situation changes, lenders may start exercising the wording in the contracts.

There may also be environmental overlay districts, historic districts, and other considerations to zoning that you have to be aware of, so I'd definitely start with the zoning regulations,  from the zoning/planning  department

you could actually paint a black line where one unit ends and the next begins, then choose colors that look good together...light gray, dark gray, tan, brick, green, colonial blue, like bm historical colors or some other palette.