I would just like to start by saying I am brand new at REI and would very much appreciate any feedback on this matter.

The whole ordinance is here.There are a few modular/pre-fab ADU designers and builders local to the Austin area. 

In that case, you probably should use a brand new lease. 

I don't know of any name brand lender that offers an easy-to-get loan based on what the future income projection might be.

With my experience in the rehab aspect and my wife's interior design expertise I believe we can be very successful in this industry.

For instance, in Sacramento the auction/bidding is done in person, on one designated day, and the property must be paid for in full immediately after that property is bought (they won't even start auctioning the next property until you pay for the one you just bought). 

(2) What is specifically written in your contract with regards to the plans/design?

Reverse mortgages are designed to separate you from your assets.  

For example, In 2021, I exchanged a lower performing rental from an "ok" area into a brand new property in a good area with good population growth and potential.

But don't forget to account for all the soft costs (design, permits, engineering, holding costs, interest expense, insurance, RE Commissions, etc).