STRs, including 2 of mine existed before AirBnB.  

We have bought loans like this from existing lender as well as refinanced borrowers into a new IO loan. 

"I have a very simple criteria for when an area is gentrifying as opposed to just generally improving: If it makes economic sense to buy (at market price) and tear down an existing structure in order to build and immediately sell a new building, then the area is gentrifying.

Also consider all lenders will require to review your insurance when underwriting a loan and it's likely a violation of your existing loan documents to let the properties go uninsured even if they didn't require insurance escrows. 

You search for existing guides, select the best and provide the link or the document to your clients.

For those holding hope they will fall and save existing deals, don't hold your breath. 

At this time the interest rates may make keeping your existing home a better option than times when rates have not risen as substantially.  

In a rare case, it could be the second lien that is forclosing meaning the first lane still exists, and you would be on the hook for that.

I recently looked at an existing STR, but either the seller did not track the expenses or they did not want to provide them. 

He tried to do patch work on this one wall with existing paint and it looked like a jigsaw puzzle :)  If you can't touch it up you're using the wrong kind of paint.