The fact that we require it, will hopefully prevent such negligence.

@Ray LaiAlthough I am not happy with this wholesaler, or the other two real estate agents that I used as references, I only gave out the contractors name to prevent anyone else from getting screwed by him.

Like most things in life, it's a double edge sword.Buyers benefits include being able to negotiate terms, lower down payment, not having to qualify for a loan with a bank (if you have issues preventing approval).  

The changes would require an "Integrated Pest Management Plan" for certain properties, add new requirements for Landlord to prevent mold, etc.

If you, the homeowner pulls permits on the home, you will sign an affidavit that will prevent you from selling the house for an entire year.

All of the above assumes that the original house needs little renovation work.Before committing with a contractor, make sure that you get with the local town to make sure that you are allowed to split the house and there are no issues that would prevent it (like egress, unit separation, etc). 

This will assist for 6 months to a year but is not a permanent fix for the root cause of the odor.  

Sometimes they can make the property negative cash flow or in a worse case scenario prevent you from even leasing the place to anyone but family members.

Unless you are on the loan they are prevented by the FCRA to discuss the property with you.

Not sure about preventing them.