If I find that two of the units in my building have bed bugs infestations, it is necessary to have all the remaining units and common areas in the building also treated for bed bugs? 

A bedbug infestation?  

Tenant agrees to be responsible for maintaining a clean environment to discourage pest infestation and agrees to report to Landlord any signs of pest problems in a timely manner.

Just reaching out to all the more experienced landlords out there- One of my Detroit tenants has submitted a complaint of bed bug infestation in all her furniture.In your opinion,- is this the owners responsibility.

I'm not super handy and would rather not have to deal with major overhauls like mold or termite infestation but I'm comfortable with painting, flooring, re-doing kitchen/bathroom etc.I'd plan on buy/holding this primary residence, but once enough capital is built up I'd be more interested in fix/flips. 

You did not fix the vermin infestation.

For instance these are what I call executive properties with many top of the line extras, in a prime location, and they were compared to older out of date homes in areas that are ghetto and gang infested.  

Just wouldn't want you to find out there is a foundation problem or termite infestation further down the road.

The tenant and her two children had lived in the home for one year, renewed, then only 3 months later claimed they had been living in a black mold infested home.

There are some gorgeous old homes on Patterson, but they have become so run down and infested with vermin of all sorts, we stay as far away from there as possible.