As I said... open a few tanks and check for backflow, visit the health department and ask a few residents if you can. 

After trying to read that I had to check a mirror to see if perhaps I had a stroke.

Those are the biggest two that are not allowed, but I would suggest checking in whatever state you are co-hosting/managing in.   

Don't think you can have homestead claim on LLC property, but check with the title lawyer.  

We've thought about seller financing, but can't imagine someone selling a $649k house for a small down payment and even smaller monthly checks.

Quote from @Lauren Samford: Check your state laws.

Check out https://www.noradarealestate.com/blog/due-on-sale-clause/in general putting the property into a land trust should not trigger the due-on-sale because of the Garn St Germain Act.

Ignore credit ratings but ask them to explain what you will see during a credit check.

Have you checked Furnished Finder to assess the demand?

I'd check them out.