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.

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.

While the low tax rate and exemptions are enticing, it is important to consider that the average house in Hawaii is more expensive in comparison to other state averages.