It will need to meet all fire and safety codes per your local building codes.Done properly a secondary unit in a SFH is the best method to generate positive cash flow on a otherwise underperforming asset..  

Regarding personal safety, as a general rule people don't walk around with cash hanging out of their pockets even in good areas.

Under pro you have literally unlimited earning potential and an almost limitless number of ways to do your business.Under cons you have no safety net. 

People flock to more perceived safety.  

Fall & Spring HVAC Service Target Date: April and October This service can aid in early detection of costly problems and save the cost of expensive, emergency service.A/C Service Includes: Check condenser coil, adjust operating pressures, monitor safety controls and starter capabilities, clean or replace filter, adjust blower components, calibrate thermostat, measure for proper temperature differences, clean condensate drain, tighten electrical connections, measure voltage and amperage on motors, lubricate moving parts.

My property manager has already told them to move out immediately if they feel the home is a hazard to them, and I’ve already told them I would do the mold test.

If you cannot afford the health and safety requirements of owning real estate, I'd suggest you find another type of business. 

I'm also sure the city or local government would love to know of this potential hazard.... and just maybe the landlord doesn't want to make repairs to this now vacant property.

We just want to be in compliance with the law and follow safety precautions. 

Selller has given "An EPA-approved pamphlet titled “Protect your family from lead in your home,”which identifies lead-based paint hazards.".