I increased the maintenance and Capex for a combined 20% ($5,832 anually), vacancy 8%.  

A blended rate is a combination of interest rates on various loans that gives the total amount of interest on loans aggregated in one.For Example:Loan 1: 10,000.00 @ 4.00% InterestLoan 2: 5,000.00 @  9.00% Interest You're blended rate would be 15,000 in debt @ 5.667%

This, combined with putting 20% down at 4.375%, allows the place to cashflow nicely.. all things being relative.

Is there a recommended option for washer/dryer that doesn't require coins/bills but instead takes phone pay or a card, so that both tenants and prop managers don't have to deal with coins and bills?

Lastly, cities/towns that have well thought out city planning and/or strict zoning if combined with the aforementioned characteristics will almost always lead to supply pressures that work in your favor. 

A good rule of thumb is to plan on spending approx $10k on all the standard items for your unit like your washer & dryer, linens, small appliances, dishware & cookware etc., plus $2-3k per bedroom.

Combine that with appreciation and it could be a viable option.I also know of two different multi family properties right near the heart of Kailua Kona that are on the market as well.

Or a combination of other factors I'm not mentioning. 

My interest in investing in the construction of a new single-family residence (SFR) on the West Coast of Florida was driven by a combination of factors.

It is the only property that I own, and my reason for buying it was because I wanted to have the freedom of renting combined with an ok investment--and that's what has happened.