With a purchase price of $80,000 and a sale price of $115,000, the property promised substantial returns with minimal investment.

I understand that because the cash flow will be delayed for 1-2 years, I am technically paying such good price for the apartment, therefore I would like to collect more opinions on this type of investment.

If we did, it was minimal at best. 

I self financed it until I had to take on some loans due to delays and cost overruns (ever heard of such a thing???).

Cons: Delays buying a house hack, Greatest risk of another repair or eviction causing a larger cash issueOption 5) Self-manage the properties -- Pros: Improves cash flow by ~$100 / unit / month, I self-managed this portfolio for 3 years and believe that I was more effective than the professional property manager, Can do this in addition to any of the above options.

Buy out the properties mortgages and sell it for a loss and try to minimize the total loss?

This step should be done carefully, with legal advice, to minimize the risk of triggering the Due on Sale Clause.Monitor the Loan: Ensure timely mortgage payments to avoid drawing attention from the lender.Legal Support: Have an attorney review all documents and agreements to ensure compliance with local laws and mortgage terms.The Due on Sale Clause is a critical tool for lenders to protect their financial interests, manage risk, and maintain the quality of their loan portfolio.

There are going to be mistakes and delays by the dozens.....

In addition buying an existing ADU has the following advantages over building one 1) typically pay less for the ADU than the cost of doing a hands off ADU addition 2) get RE purchase financing which is superior to financing that is specific to the ADU addition.  3) there is no delay between financial outlay and income when purchasing an existing ADU.  

Apologies for the delay in responding.