But in smart buying, if someone has enough cash to pay cash for a property, they could easily stash a good chunk of that away to cover downed months and still leverage to increase the overall returns on their portfolio.

Absolutely, real estate can still be a smart investment—even in this market—and the Panhandle is one of the best areas to consider right now.

Our AirBnb guests not only skew younger (which is fine) but they also seem more tech-savvy (comfortable with our smart locks, remotes, etc.).

Ditto, I use PriceLabs for my STRs - here is a nice writeup ...Airbnb Smart Pricing Vs PriceLabs: An In-Depth Comparison For Hosts | Boost Your Short-Term Rentals

I am at this point looking an easy/smart way to put something in between.

Umbrella insurance can be a smart way to shield yourself and your partners from potential risks that basic policies might not cover.From what I’ve heard, local insurance agents familiar with investment properties in your area are a great starting point.

This is a great idea that I think I will incorporate.Your point about a contingency line item is smart, I will need to talk to my lender about that possibility. 

If you were in my shoes, what real estate strategy would you recommend for scaling quickly (but smartly) so that I can replace a good portion of the W2 income from real estate investing?

be smart make the right choice

Probably not; I've done pretty well myself from them, and you're a smart and nice guy so I would be shocked if you *weren't* killing it!