I also just wanted to let you know for the sake of your calculations, I'm a loan officer and (depending on your credit) even with a 15 year note, you'd be lucky to find a 4.25% mortgage on a regular sfr with no points nowadays, let alone a jumbo loan like this would be.

That's how people are nowadays.

With the high construction costs nowadays it's hard to add that much value, plus ADU's don't sell at the same $/sqft as the regular house, and there's not a steady readily available comparable properties to base valuation so the easiest method is replacement cost.I hosted a Meetup and wrote about ADU's on my website.

But it's hard to find the real flip deal nowadays.

Greg:    First, do not get discouraged by anyone, someone else is doing it so you can, not going to be easy.If not done already I suggest to look into this:Enforce that PM uses a great website for rental screening, ones with a background check and choose the best tenants possible.Review you leases to close any pitfalls and enforce the lease to the T.Keep the units in good shape and keep extra cash reserves ( fixing + trip expenses )Tiger than normal lookup on the PM ( have second PM line up ), vacancies, unit showing costs, repairs, fees, etc,  require a once a week normal operations report and a once a month full operations report.Family, friend on virtual assistant that regularly drive by the property and reports to you, or if cash flow allows and deem beneficial you can install security cameras and remote view activity on the property, nowadays there are lots of options.Check if feasible to get a home warranty plan for the units so some pain issues are self-managed by the tenant via a phone call to the warranting companyIn which city/state is the property? 

So nowadays I start on the telephone by telling them I am an investor and advise them regarding the economics of wholesaling their house. 

Marriage is like playing Russian roulette with 4 out of 5 bullets in the chamber nowadays.

Cash flow, grow wealth, every other generic buzz word you see on BP regarding this

People aren't suckers nowadays.

I run a construction company more than working as a lawyer nowadays.