Tell them they have to go, no matter what, but that you will reward them if they leave peacefully and/or quickly.

Consider having the peace of mind of a long-term tenant (you're not worried about short term trends and occupancy - assuming you've screened and placed a quality tenant).

If your current tenants are exceptional and the financial numbers still align despite the lower rent, there's something invaluable about the peace of mind.

Find a peaceful resolution. 

If there is nothing in the lease then you should at least have a noise, or other disturbing the peace clause in the lease that you can fallback on?

Tax prep is a post mortem while strategy is a pre mortem.I always tell people looking for a new CPA team to fully understand what is and is not included in a quote, what could change future pricing and what your ROI will be (including tangible savings plus your peace of mind).

Do not let people like that steal your peace of mind or your satisfaction with what you do. 

So we have gifted nieces, nephews, family friend’s children money for their college fund, and some select charities.my son recently has talked about a few paths in a couple months: 1) green peace 2) continue formal education in Europe (he is fluent in German and has some Spanish but can pick up languages fast - he got this from my mom (skipped me)) 3) RE investor, but he does not have an understanding what it means to be an RE investor.  

@David PereiraBuying a property with all cash can bring a lot of perks, like more money in your pocket, no need to pay interest, a better chance to win in bids, easy process, and peace of mind.

I would replace both so that you have peace of mind and don't need to rush when a roof leak appears or the HVAC stops working.