You’re in an interesting position depending on how long you’ve lived in the U.S.

No offense, but absolutely, positively in no way shape or form would I, as a lender of over 30 years, provide a loan to someone with no out of pocket capital.

We took the reverse action and started lowering asking rents until they moved.I suspect the reason that one property of yours turned quickly is because your asking rent was very favorable vs. local competition. 

At some point you have to make the actionable plan.  

There are many reasons that adding a single ADU in southern CA is a less than ideal RE investment (i will post a list at the end) but the negative initial equity is a primary reason as the initial negative equity position consumes the initial cash flow and can take many years to recover.As for converting your home to a rental….

I am creating a 5-7 year plan of action for my family.

He'll have at least $2k per month in positive cash flow and tons of equity when it's time to find the next home in some years.

I hope to use private capital to fund the entry fees in second position.  

And, I think you can rest assured that somewhere among your acquaintances is someone who has noticed what you've been doing and has been inspired to take action.

Thanks for your positivity.