I also got a written and signed agreement from tenant that is notarized for him to vacate on or before 2 weeks deadline after closing. 

The demand for vacation rentals in places like Destin, 30A, and Panama City Beach remains strong.

Quote from @Collin Hays: I visit fairly often with investors looking at a certain vacation rental property to make an offer on.  

Tell him you'll give him a call :) This is one of the reasons why we tell tenants they need to vacate the property for any major repairs.  

Unfortunately, relying on a "nice card" approach doesn't always ensure that tenants will vacate the property in good condition.

I use Beyond pricing in my vacation rental markets and Pricelabs in my city/mid-term rental markets.

These 2 platforms don't focus on MTR but vacation rentals so using Furnished Finder is a better way to get those longer term folks.I have always been a bit concerned about the area's penchant for restrictions.

The relatives are vacating. only 1 tenant wants to stay through ownership change.

If you can hold on until the end of lease term, you can give a written notice and also send an email which would be Notice to Vacate. 

But tell them what you are doing precisely - vacation rentals, not regular rentals.