The house currently rents for $1450/month, we have long-term tenants, and we use a management company.

I used to live in northern Illinois, so close to Wisconsin - there are several smaller towns around lakes that would be good for short term rentals. 

The downside of this strategy is that the borrower has some leverage to negotiate terms that benefit them in exchange for the Deed in Lieu.Plan executedGiven that we had ruled out the first two options, it became clear that we were going to end up taking these properties back along with inheriting any accrued liability.

If you do have to sell in the short-term you might not recoup all the money you put in.

Many lenders offer flexible financing terms up to 85% in some instances for investment property transactions. 

I would try to find a short term/mid term rental friendly agent who might be able to give you super accurate feedback on the market

You need to have had me aware and agree to these terms and conditions.

Namely, there is 2 major factors, price and TERMS.

How do you estimate just how many residents will stay long term vs. decide to leave or perhaps pass away during their stay?

If it's a single family house, it should be tenant responsibility but if it's a multifamily, that's when you may need to take care of it - it depends on your lease terms and should be stated there so both landlord and tenant understand whose responsible for it.