3) What's a "dark horse" market that might not be incredible at the moment but has all the signs of future promise?

It is not your font and it is not the color of your mailer.

Simple to use, 4k video, good colors, detail, and light balance.

I would say one of the biggest things I see problems with is guests coming in and clicking buttons right away.I think it is necessary to have laminated signs that tell guests how to use things like pool + spa remotes, A/C, specific lights if they are high tech (mood lights, color changing lights), and other things that a guest can get confused on and mad that it isn't working properly.

Needs to be in writing (email etc.) but generally, we don't allow any changes until at least the 1st full year.After that, use your best judgement and go on a job-by-job basis and inspect (for example: they paint one wall or room before you let them paint multiple spaces, AND the color is approved in writing as well).

I think quartz is my favorite because of the color options, robust, less/easier maintenance.

When analyzing why a property may be on the market for longer than comparable rentals start with assessing the condition of the home (does is show and smell clean, any deferred maintenance, dark inside...). 

Agreeable Grey for a long time was the color to paint rentals, that is changing.

Light color roof and exterior to keep house cool, for warmer climates.

(Again--this is WAY outside my area of expertise, and I don't know anything about the legal aspects of sales to a buyer outside the US, so it's just a total shot in the dark).  ...but I'm interested to hear your take on it...Good luck out there!