Do you think the agent is new (naive) or they do not have any moral compass?

Note Investing is all about serving others with compassion and caring.  

There are different kids of big-box brokerages and as a new agent I would steer clear of old school and focus more on brands like eXp or Compass or Real, brokerages that give you opportunities to join teams and have updated marketing and more cloud availability than in-person requirements for new agents.

Smoking hot deal and execution, and love the care/compassion you showed the tenant.

Other large national brokerages, such as KW, Compass, etc. can also likely offer this.  

While I completely feel for this person and their daughter, you have rights as the property owner. i would start by reviewing the laws in your specific state. once you know exactly how you can proceed legally, i would suggest you start with a friendlier approach. not that it's necessary, but maybe ask the agent to help them find a replacement rental. maybe you offer a small cash-for-keys, just in good faith and understanding. not saying you HAVE to, but you might find it way easier to vacate them with some kindness and compassion, rather than playing hardball. if that doesn't work, then take the necessary steps to vacate them through legal means. 

Meg and Russ Wood from Compass Realty were the BEST!

It can be a challenge balancing financial mindset with compassion mindset, they will often be in conflict.

I don't have that answer, but you have to face your family and sleep at night, so hopefully you have moral compass driving your business. 

Remember, the COE is intended to apply "all the time" and be an overarching moral compass.... remember, many more "hard core" investors do NOT become realtors for this reason (and I THINK the same reason for commercial agents/brokers).Good luck.