For me, it was that I didn't have much cash on hand at the beginning to invest for only modest results so I needed to be really conscious about how much cash I kept in a deal.

Hazard Disclosure Booklet, and related Optionor disclosures, containing Environmental Hazards,Lead-based Paint and Earthquake Safety.e.

You'll also likely need to do a Phase I Environmental (again in the $2500 range) which pulls up the history of chemical spills, soil contamination, water quality, etc. 

Zoning  and environmental concerns greatly affect value.

You may want to also pull out statistics in project cancellation/project shutdown due among other things, State induced strict compliance to the letter, contractor's compliance and liability costs (biggest reason why significant California contractors are put out of business aside from tight competition), it's just next to impossible to earn contractor wages based on economic conditions (that being current prevailing economic depressed consumer wages cannot support re-construction costs or that wages to property modification ratios is not sustainable in long term basis), indicators, and indices (unit labor ratios, material integrity and application ratios, Local, State, and Federal (labor, occupational hazard, environmental) compliance costs, and certain and uncertain risk factors.

I offered him 6% interest, he said 'he could only take 3% in good conscious' :-) . 

I like destination tenants ( barber shop, nail salon, restaurant, doctors office, environmentally green dry cleaners, gyms, karate schools, etc.)

We have a 2 yr old, so we're obsessively conscious about smells and washing).

Has an environmental and survey been conducted?

You could jump through hoops and get a "Letter of Environmental Protection" which will allow you to rent to families, but it will devalue the property and increase insurance rates.