Under the FHA rejecting a person for the ESA dog is a form of discrimination against those with disabilities.Your post suggests that this person has passed all your screening criteria except for the ESA dog.

They are business credit cards which report to different agencies than your personal credit, so it wouldn't affect your personal status at all.

If a buyer has good credit he can get a personal loan to buy a property, and hence “nothing down”.  

Personally, I'd never buy the biggest house, or the most expensive house on the street.

Quote from @David Eyal: This is actually very simple: don't get involved in personal issues.You offer them a renewal.

‘imagine you were looking to buy something personal like a shirt, or a watch.

I will say that if you get some ducks in a row, things like a good cleaner, handy person etc, you could manage from farther away if you find a deal or area you are interested in.

We took this approach because even though the house is an STR it is also one we want to use as a family a couple times per year, and we feel we have our own personality as hosts, so we were particular about what we wanted. 

I  would look at your town regulations and see also if they have any unrelated persons ordinances and what they say about boarding houses. 

But it's tough work and doesn't always pay off.I personally think the big profit is in new development or a project.So, I'm wondering: Is starting something new a better bet?