He intends to turn it into a short term rental. 

Hi Nida,I'm a bit late to the party but better late than never I guess lolIn the search bar here on Bigger Pockets or even a Google research will reveal a lot of info about certain companies.I'd always like to joke around and say that "Google is your best friend" when looking to work with someone new lolI'd like to second Jason's comment who has been around the turnkey game for a long time and has probably conducted due diligence on many if not all turnkey providers over the years.Not many have stood the test of time and I'm proud to say that we have.Not intending to plug my company as we have many battle scars that started from day 1.But still here and still battling away 🤓Why we survived and thrived unlike many others was keeping our operation small and boutique and only doing deals on our terms.Low volume sales and thorough investor pre-qualification (As not everyone that has a pulse is necessarily a good fit for what we can provide).Some investors did better than others but one thing I can happily say is that we always did our best for all.I believe a very important component to any "true" turnkey company is that the penny ultimately drops must drop with them.Meaning, if you invest and things don't go the way as planned it is entirely up to them to rectify.No finger pointing or passing on the monkey to someone else (Like a realtor, contractor or PM).A true turnkey company stands behind it's properties, rehabs and in-house property management.Key phrase here is "in-house property management".Everything must be under the same roof and the provider must take all responsibility for the outcome of that investment.Wishing you much success

We specialize in short-term rental investments through our integrated real estate, mortgage, and property management services, delivering expertise at every stage of the process.

My name is Rami, and I’m a short-term investor doing business in Texas, with a strong focus on the Dallas market.

I'd sell because you are reaching the time when you lose the cap gains exemption and that $24K would take over 2 years of renting to get back.I had a condo that I owned for a long time and I sold it despite it being paid off and having long term tenants. 

Congrats on taking the leap and your success so far!

They also have a home vacancy tax in a lot of areas which applies to short term rentals. 

I’d love to hear your experiences, opinions, and any tips you might have for successfully implementing these strategies.

If I understand correctly; the seller would receive 80% ($40,000) directly from the mortgagee at closing and would enter into a personal agreement with me for the 20% down payment ($10,000) in which he would be reimbursed separately from my mortgage payments at a separately agreed upon rate and term?

Being out of state, I would suggest vetting your "team", meaning find an investor realtor, lender/s (hard $ / long term), property manager, contractors, etc.