Will also suggest that my neighbor drop my tenant a letter (he has been demanding the tenant's contact info, which I have declined to furnish).

Rincon is very seasonal, so in the off season you can even rent for 6 month as a long term furnished rental. 

A travel nurse friend of mine wants to sub-let her furnished apartment in Birmingham to another travel nurse or business executive.Question: how does she protect all parties: her landlord (who is in agreement with this idea), the renter, herself, and her property?

Every Arbitrage deal I complete, that's part of my conversation with the owner/Landlord, and in every deal it's the same response; they don't know STR, they don't know how to do it, how to furnish for it, how to best market for it, the constant over-turn of tenants, coordinating cleaning vendors, active marketing, it's all pain points and while yes they see the revenue potential, it requires an operation they simply don't have commanding knowledge or experience in. 

Just today, Moody's has threatened to reduce the United States credit rating to AA.An article that I just listen to furnish by Keith on another post was even more scary.

Naturally you'd buy based on good fundamentals and the gamble is just on the startup costs of furnishings, vacancy, etc.

Fully furnished and all furnitures go with the house. 

Is it better to have the places furnished or not?

The questions off the top of my head are what premium could a landlord charge for renting a home fully furnished vs unfurnished and also short term vs yearly?

These #'s were furnished by Florida Association of Realtors.