While my husband and his ex make a similar income and do not exchange child support due to us pointing that out in court a couple of years ago, she actively request all financial documents that she possibly can and examines our taxes, etc. 

Stats can be foundhttps://www.ramaui.com/housing-statisticsOr for all islands herehttps://www.hawaiirealtors.com/resources/housing-trends-2/Your realtor can produce more specific stats on your area of interest.

Umbrella policy is pretty cheap and can protect you with $2M+.100% recommend being pet friendly due to the stats posted above. 

I would think your insurance agent might have access to some historical information for a specific area as they would want to examine this closely for their underwriting.

Again, others might feel differently here.3) property level due diligence: (takes seconds to weeks per deal): here is where I drill in with the low-level details.a) pro forma popping: I examine all the assumptions, and see if they are overoptimistic or not.

Does anyone know stats on this or have personal experience in this region?

Examine the bottom half from every angle - how much you can make, what else you can get for your money (don't worry about how much you make on these, they are time suck and the lower half of your portfolio)That's a good place to start.

You can make the determination by examining the mechanical systems yourself and finding out their age or hiring an inspector to evaluate the systems.

As @Robin Smith mentioned, for assessing demand I used FurnishedFinder.com/stats; you can see demand data for a given city and some pricing data too.

I use the FF stats page to see what average prices are by unit configuration and make sure I'm at the high end.