Brown: I use https://www.bestwyomingregisteredagent.com/Very simple, 100% online, they are responsive if you need help.

I'll keep this short and simple.

.: Before the fur starts flying, can I at least make one simple statement about this situation?

Somehow, I had it in my head that I didn't want to do a cost seg, I like to keep things simple and cost seg seemed not worth it, so I have been investing for over a decade before we did the first.

Keep it simple - sell the property and let each sibling do what it is that they want.If you keep it and do a refinance(to pay for the bills)Who will be on the loan, will it impact everyoen's DTI?

I also agree that RE appreciation is unlikely to match the last dozen years, but you never know.Where I am unsure we agree is that paying $450k to improve the cash flow ~$3k (your numbers but I expect my delta wold be similar meaning both my cash flow estimates would be worse than yours but both would be worse by the same amount not affecting the difference) makes sense especially if the cost of having the extra $450k is only 6% rate which is historically simple to beat via numerous investment options and hopefully no one is investing in RE for an expected of 6%.  

Insurance protects your property from paying out of pocket for damage, plain and simple.

It's simple interest income (unless you do it in an IRA).

I have never paid for a course but spent $15 on a book about Airbnb rentals and it's simple math.

I recommend a simple spreadsheet to check your math and it will make it simple to adjust each year.End the complaints.