Focus on paying them off (smallest to largest), and you'll be living large in 20 years.

The struggle comes when you plan to sell, pay close attention to how the bank would treat the loan in the event you would sell.Even though its a bit more work, banks are typically open to these loans as it provides them with additional collateral in the event of default.  

The 90% they are paying you back is probably 1/3 of what they're actually making by you committing to a deal.

Owning a duplex at 20 is a huge accomplishment, and it’s inspiring to see you’re already planning your next move.From my perspective, real estate investing is a long-term game focused on building equity, paying down debt, and maintaining stability over chasing short-term cash flow.

Will it pay the full PITI plus Capex, management fees, maintenance etc?

My goal is to offer an affordable monthly payment that competes with renting a comparable property and offers a benefit to paying a bit more to "own". 

Less licensees paying into the pot means everyone's costs go up.

If your willing to do so, you can live in the casita and then rent out the main home and have your tenant pay the majority/all of the mortgage (depending on what type of deal you find obviously). 

My worry is that since he has built a 16 year track record of always paying his pref and returning capital on time, that he is now overleveraging.Does anyone share this concern?

Im thinking about paying the bank the 50lk that we owe and the taxes.