Look at how they present themselves and see how they’re living now and the conditions they will be leaving their old place In. 3x of rent should be their verifiable income(minimum). see what they’re trying to do with their lives and where they are mentally. 

They shouldn't have a deal-by-deal mentality to try and squeeze for every dollar of profit.

Just started on airbnb renting my new basement apt and wonder how to cross promote in addition to just using Airbnb - which has been great - for September, but for slower months, I wonder if I should look at VRBO, etc...Thoughts?

So you are spending your mental energy on the wrong things.

I don’t have any personal experience with them but see them online doing a lot of promotion.  

To be a landlord I’d get a counseling / mental health degree to deal with insane irrational tenants which is 99% of them .

Second, use the above to plan your exit strategy: Sell the property: If the property Value is > debt on the property (enough to cover your investment and hopefully some ROI)Rent the property: Debt is > property value (fight the foreclosure and Airbnb it to savage your investment) Of course, there are more factors to take in consideration as each case has its own nuances this is just representative, I do not by any means promote the rental of properties under foreclosure and you would have to check with the HOA if it is even allowed.Short answer: If you buy an HOA lien most likely the outstanding mortgage will foreclose on the property and you will lose title once the foreclosure process is complete. 

I have heard the saying "Live where you want and invest where it makes sense"  I am trying to break out of my DIY mentality and investing out of state forces me to put together a good team. 

Bigger Pockets does not allow us to promote openly in forums....which I'm kind of glad about.

The mental illness alone shouldn’t be much of an issue (unless it makes them violent), and assuming someone else is sort of looking after them.