They will have 48 hours to vacate and if not gone, constables come a knocking.

My goal is to live in the home during the winters, maybe 3-4 additional weeks for vacation, then rent it out to help cover the mortgage the rest of the year.  

Which reminds me that I should mention that I’m not opposed to living a not-so-luxurious lifestyle in the short run.

This would likely take coordination with a tenant at some point - (ie - plenty of notice to them that they must vacate in order for you to sell the property)Since your current home is free and clear -  you could do a cash out refi or take out a new mortgage on the new house to be able to buy your paren't house and pay off the mortgage.  

As our team has grown, it's become easier to cover responsibilities if someone quits, goes on vacation, or if we terminate employment, compared to when we had one or two homes. 

Provided I can establish a solid investment plan tailored to their financial needs/comforts such as debt ratios and income, they would be more than happy to offer me some financial control.Additionally, If I wanted to, for the sake of building my own personal wealth, I admittedly have the luxury of taking a loan from my parents.

You should treat it as a luxury package rather than regular STR. 

All a mid-term rental is someone staying not permanently but longer than on vacation.

However what happens when the tenant vacates and now the unit has to be turned over/takes a few months to find a new tenant and during that same period of time the sewer line goes and you get hit with that $15,000 cap ex expense in addition to the vacancy and turn over costs.

Rodrigues' recommendation may change this), but my next question would be, are there any cities/markets where 1 of the following are true: 1) You have family/friends that live there, 2) You travel there frequently (either for vacation, work, etc.), or 3) Somewhere else you've lived before AND know the area well?