To get desired asset protection, you need to keep separate books for LLC.

As a property owner, I desired from RDU clear expectation on the range of dates during which the money would reach my business accounts.

The house in question is in a very desirable and stable neighborhood and rents fairly easily.

The goal would be to Airbnb the place out so that we can cash flow more than would be possible with a long-term rental, and so that we would have access to the home for ourselves when desired.

There are some in the nicest areas and you'll be paying 80k+ a unit there...in some of the less desirable areas of the city it could be 20-25k a unit.

The rest are aesthetics choices that need to be desirable in 5 years.

The results seem to be great and hopefully are worth the sacrifices.I would not desire to make such sacrifices and believe that, with leverage, the sacrifices would not have needed to be as great.  4 years without a vacation! 

I'm not sure if there are areas where all the seasonal people want to be and other areas that are not as desirable.

I suspect the percent is about the same today but I do not desire to go through 1800+ billionaires to determine which ones have significant RE holdings.I do not classify the billionaires that invented something or started a business with those that made their wealth by trading publicly traded companies that they were not an insider. 

If you want to eventually live in it, the current income becomes less important, but seems like you can get to 1% if you do some repairs and raise the rent.If this is a buy and hold, the long term desirability of the neighborhood and big picture changes (is this neighborhood gradually getting better, or gradually getting worse?)