As mentioned everyone's strategy is different, I'm risk adverse & enjoy liquidity.

Answering any post that starts with "I have one million in liquid cash and not sure what to do with it".  2. 

But to answer your question, I'm cool with my daughter living with me until she's around 30.

Very cool!

Pros could be: Clean water + tub for each guest; on a well, so no water waste concern; can make it design-y + cute; can be used winter (hot water) + summer (cool water); goes better with forest location of the home than a traditional hot tub might; will hold same number of guests as hot tub would (2 people in each tub).In researching I have seen some people on Airbnb have these checked in amenities as 'hot tub', some 'private hot tub'.

Why would you want to double down on the biggest risk involved with real estate, liquidity risk?

I've heard the political temperature has cooled there, but I fully agree that would be my hesitancy as well. 

Multiple improvements done on this duplex in 2021, including new roof, gutters, flooring, drywall, electrical, appliances, and heating/cooling unit for the second floor.

Liquidity. 

That's a cool idea.