@Katherine RossellAs long as they are taking care of the trash and none it accumulates or come back to you, then no big deal (unless board of health gets involved).If the fleas are just downstairs and you get it early enough, then just downstairs. 

@Robert PedNot telling you to call the board of health, but check your laws on it as in some states, it doesn't matter who brought it in. 

due to health reasons I personally can no longer turn over units for new tenants to move in.

They would provide CNAs and other medical professionals dressing, eating, cleaning, etc and other basic living and health and medical services.I'm interested in connecting with anyone who's successfully converted SFRs or MFs into independent living community rentals.What's been your experience?

If I don't have new tenants locked in by next week, I'll either change my pet policy and install a fence to allow that or adjust the rent.  

Write down all of your benefits (health insurance, staplers ;-), day care reimbursement, cell phone,...

If your local area has the same demand as I see here, you should be able to set your own criteria - Local landlords will not lease for less than 12 months - they require parent co-signers, not a pet deposit, but a non-refundable pet fee - still responsible for any damage done by the animal - If you make your property as bullet proof as possible, there can be a lot of money to be made 

Think about what you ideally want or what you'd struggle with from a lifestyle/noise/schedule/pet standpoint.  

I have a seller in my area looking to get out of his property so that he and his wife can downsize due to their current health issues.

If he were good with the situation, I wouldn't know about it or be posting here. ..He is, unfortunately, after multiple mental and physical health challenges, quite emotionally vulnerable.