How do you find and compensate a good designer for overall material choices and color selections? 

What color do you think goes well with the repose gray of the walls?

I've used such for projects that ran long in the past, while interest rates rose again and again.

So, whatever it is... eat the same meal, listen to the same song, wear the same color, etc.

I have had mostly great guests, but the few that I've had that were terribly messy (much of what you describe but also smearing pizza toppings on the floor, having an easter egg hunt (I found some of the eggs) with chocolate in fabric and pink maybe egg coloring staining two sets of sheets) and yet were given 5 star reviews from prior hosts.  

I made an Excel spreadsheet and color code the ones that are higher in the red or orange colors, and low balances in green.

@Scott Mac That sage color is gorgeous!

Vibrant colors, wallpaper, etc.

having an incredible onsite manager, adding colorful flowers to perk up the curb appeal, paint the windo shutters to make them pop and renovate the interiors.

The Honeywell 9000 color touchscreen thermostats are very user friendly and have 2 different levels of locking the controls.I recommend these over any other thermostat.