If you don't get a solid response, I'd recommend contacting your local Real Estate Division and asking personally.I asked the Nevada RED about a few things specifically pertaining to my situation that other people gave me differing advice on.

Any potential issues with the IRS, or with umbrellas not covering “partnership property,” or complications with title if one of us dies suddenly, etc - any red flags I should be aware of up front with this sort of structure?

And this is why I read the meters in my MF properties (to make certain the rate is at 0.000/the red arrow isn't turning).Did y'all check the meter to see if it's moving?

But every municipality has its rules and that has nothing to do with Red, Blue, friendly not friendly . . .

That’s not red, blue, or purple, just the reality of more investors/listings in the mix than we had 3-4 years ago.Quote from @Bruce Woodruff: Quote from @Cliff H.: And looking 5 years out I fully question whether STRs will continue to show greater returns that MTR/LTR rentals, particularly those rentals already focused on niche markets for better returns. 

Even if I can remodel, will there be any red flags holding this quadplex as long-term rental units?

Also, would like to hear if anyone has used Red Door property management and what their experience has been.  

If they can't or won't do that then it is a red flag for me as a property manager. 

I am not interested in going any further.Definitely alot of red flags for sure. 7 days is short notice, but i'd also reach out to AirBNB to cancel because your "uncomfortable" with the reservation.

Especially if the property isn't/wasn't habitable.One call from the tenant to code enforcement can cause you month's of red tape, bureaucracy, hearings, and expenses.