So we (wife and I) are ready to make that final push towards retirement with long term buy and hold properties!!

My wife Jen (a real estate agent) and I are real estate investors mainly interested in buy and hold single family rentals, as well as flips. 

Leave or stay it's a game I like to call Melanie Wins.

Are you essentially acting like a contractor, but just within an airport environment and selling the renovation while your client holds the lease or is there another process I'm missing?

Considering your situation, holding onto your current duplex with its strong cash flow and exploring refinancing later when market conditions are more favorable and you have built up more equity seems advisable.

I am very new to the real estate game and wanted to gather some knowledge in the general area. 

Investment Info:Single-family residence buy & hold investment.

Holding the note that you originate is a depreciating asset.

Their expertise has value, they now have good skin in the game, and they will/should agree to share their thought process when they say "that's a good idea" or "that's a stupid idea." 

On the flip side, holding onto equity allows you to maintain the proven income stream from your established STR and retain a valuable asset.