They're put through a stringent background check and receive training through an award-winning "Agent Advantage" certification program. 

You should look into the house as a prospect for buy a tax lien certificate.

There are NO certifications required of an animal at all,  the only verification you can do apparently is to the tenant's need, from the provider who cares for the tenant.  

Services You Cannot Shop For $672Appraisal Fee $550 Credit Report $73 Flood Certification $10 Verification Fee $39C. 

You also need to look into Mortgage Credit Certificates.

@Michael Kalis I am fairly new to actually investing in the city of Detroit rather than the suburbs but the one thing that you did not mention and I think it has been overlooked on most of these posts is the new rental and lead certification process.

They do not need to disclose the condition that requires this only that one is needed.I also believe you can ask for certification of this animal being a certified service animal.You can't charge extra for as service animal as these are not"pets".The husband thing is another wrinkle.

Use an estoppel certificate to ensure all parties agree on the lease terms, rent rate, deposit, etc.

The tenant must provide a letter/certificate from a doctor and you then must accept the animal as an ESA.

But I also mentioned that I had a case where I asked for and received a "certificate of insurance" from the tenant certifying he had it, then a few days after sending me the proof, he cancelled it.