On page optimization (essentially rewriting all your content so it’s unique and will help rankings), off-page (all your local listings, directories, etc), back-link building, consistent content creation, getting that content on high authority pages as a third party contributor, ideally linking back to your site, etc.

Thomas S. has pointed out California investors enjoy some unique tax benefits... knowledge is the key.Just my personal opinion: ALL investments without knowledge is speculation...

There are also some unique toilets for confined spaces.

If there is a ton of combined equity you might be fine. 

I would probably take the trade off and combine the two for more capital.

They're also super responsive on customer service, and I like their reporting.One of the founders was a founder at RealtyShares, and they came out of the Y Combinator startup incubator, which often (not always!)

You said the rent and mortgage are 1527...why are you combining those two numbers?

I would suggest you compare that option with others such as multi family apartments, other commercial RE assets, notes, flipping, a combination of several of these, etc.

Unique Amenities that help in bookings?

Some quick searches seem to indicate that the market in Oahu is somewhat unique (rules limiting short term rentals, lots of leaseholds, etc.).