I personally wouldn't hold a property without it.

Out of all the tools I would personally suggest Pricelabs for sure.

The new person must complete an application and pass the screening.

Quote from @Elizabeth King: I have a property in my personal name that I plan to rent annually. 

I love finding VA Assumption Loan deals and have personally secured one so far as a rental property with a 3.3% interest rate. 

I personally think this is the direction booking sites need to go.

You absolutlely need to be direct to seller or have close, personal relationships with wholesalers and active agents.

I personally use Bnbcalc: https://bnbcalc.com/?

I know one person that did this recently and was able to negotiate no money down and 12% over 5 years but this was probably in the mid west.

I've consistently written about the forces of nature and her current and future effects on the real estate market (even while often being ridiculed and politicized on this very site for it) regardless: I personally moved and invested in coastal Oregon in 2018 from Venice Beach Los Angeles partly as a result of the trajectory of climate and have assisted several clients that specifically purchased on the Oregon Coast for their own 'climate havens,' investment and future retirement homes.