So i spent a total of 42K and the 3 apartments will bring in 20k per year (Cash flow a little less than 9k) Just do the comparisons - what are other duplex or 4plexes going for?  

It would be a good Idea to also check with one or more independent agents and get comparisons. 

And if you are planning to self-manage that improves your cashflow in comparison with an out-of-market property where you'd pay 8-10% in property management fees plus I believe that maintenance/capex costs are lower when you manage as opposed to a 3rd party.

I analyze the property, and estimate rehab costs (with inspectors and contractors), add a buffer for unexpected repairs, as well as an ROI comparison of setting the property up as a rental vs. selling the property.If I am ONLY presenting the deal to the investor, meaning I am NOT buying the property myself or setting up any type of assignment, just "connecting" the investor to the property and running the numbers.

The only number I was concerned about was the monthly payments, which looked great in comparison to the SFH I was looking at.

That's a good way to start comparisons.

We have one set now and are looking for another for comparison.

The original owner definitely prioritized the main loving space size over the bedroom/bathroom.I have read through the new/updated rules about permitting Unpermitted ADUs, but not quite sure how the ideal sequence would go if we also want to expand it.

As a real life comparison in my market...you could pay $50-60k cash for a property to make $700 a month tops.

“The current month’s (September) inventory decreased 5.5 percent from last month’s total of 963 homes.”For home sales, the increase is magnified by the quarterly comparison, as well.