I think they operate in 36 states.I would lease the house to them for an estimated but not guaranteed $x per room.   

For anyone that hasn't used Doorvest, it's a simple website where you put a $1000 deposit and they send you curated list of houses they buy that need renovation, renovate, and then tell you a final purchase price along with guaranteeing things such as first year rent will be 100% covered by them even if they don't find tenants.

However, it adds complexity, costs, and doesn’t guarantee tax savings without proper structuring.

Virtually guaranteed it's before your house is back to pre-destruction condition. 

You’re told you still have to personally guarantee the loan BP poster: But my properties are guaranteed to appreciate 5% each year in perpetuity if owned in an LLC

Court ties you up for a year to a year and half with no guarantee of the outcome.

It's no guarantee but it's a good place to start.

If a guest finds someone elses hair in the hot tub upon check-in, you can almost guarantee a bad review.

It depends on the definition of guarantee.

This relationship guarantees income, as payments come directly from these organizations, not the individuals.