They can be sold to owner occupants that get a conventional, fha or Va loan.

20 to 25 year amortization is pretty standard for commercial loans, in my area at least.

Consider FHA loans for lower down payments and reserve for repairs or upgrades.

HELOANThis takes second position and is a closed end loan, meaning it's given as a lump sum similarly to a "regular" mortgage.

Pretty much my first step should be work as a loan officer and then the rest will come to me?

This method is particularly relevant if you're in a market with high rental demandI would like to know the appraiser who valued an ADU using income approach for a conventional loan.  

Great tools that get updated regularly.I am on the lending side of things and would be happy to hop on a call with you anytime to discuss financial strategies and help answer any questions you may have about nearly any loan product available to help you on your journey, even if they are not products my capital partners offer.We are all here to help you learn and grow.

From there, it's normal DTI/Credit/Cash assessment for the new loan to determine whether you can afford the loan. 

Great tools that get updated regularly.I am on the lending side of things and would be happy to hop on a call with you anytime to discuss financial strategies and help answer any questions you may have about nearly any loan product available to help you on your journey, even if they are not products my capital partners offer.We are all here to help you learn and grow.

However, the high down payment and reliance on a DSCR loan could limit flexibility, especially with your DTI constraints.