For those with coverage, whether an occurance of it is covered would be based on how it occured and did/should you have knowledge about the potential for mold.

What are the biggest challenges people have faced with this. Also how do I make sure to get good tenants?

We don’t know any PMCs to recommend in the area mentioned, but since selecting the wrong PMC is usually more harmful than selecting a bad tenant, you might want to read our series about “How to Screen a PMC Better than a Tenant”:https://www.biggerpockets.com/member-blogs/3094/91877-how-to-screen-a-pmc-better-than-a-tenant-part-1-services-and-processesWe recommend you get management contracts from several PMCs and compare the services they cover and, more importantly, what they each DO NOT cover.

We don’t know any PMCs to recommend in the area mentioned, but since selecting the wrong PMC is usually more harmful than selecting a bad tenant, you might want to read our series about “How to Screen a PMC Better than a Tenant”:https://www.biggerpockets.com/member-blogs/3094/91877-how-to-screen-a-pmc-better-than-a-tenant-part-1-services-and-processesWe recommend you get management contracts from several PMCs and compare the services they cover and, more importantly, what they each DO NOT cover.

A mass shooting occurred tonight on the street next to the street where the property is located, leaving nine people shot and one dead.

As is often the case, it harm low-income populations most.

It might cause me financial harm as I have to sell more stocks and might pay short term capital gains vs long term capital gains.

So now your causing "harm" to the entire state of CA with such added debt load. 

I say to look at these hard because these items can occur for a period of 12 months possibly without major issues of seeing large cracks or settling if a lot of water hasn't been present in large volumes.

General improvement is not gentrification.So gentrification only occurs in areas with the right infrastructure that have hit bottom.