Bryan you just need to make sure you go through a bank with delegated authority having no "over lays". 

The application is done with IRS Form W-7, and foreigners must provide original certified identification documents.IRS Form W-7IRS Form W-7 InstructionsThe IRS has 'Certified Acceptance Agents' who are authorized to certify foreigner investors’ original documents and process the application.

—An heir would first have to have the authority to sell the property which usually requires probate—what advantage is there to the heir as they have no liability for the debt?

I was just made an authorized user on my parents card so I can start building credit

If you wanted to go this route.If you want to keep your tenant, have them sign an agreement not to have the named subject at the property and anyone else not authorized on the lease or section 8.

If the dad is solely responsible for the rent payment and if you don't want to redo the lease completely, she could be added as an authorized occupant.

Perhaps the most comprehensive study was done by the Appraisal Institute and the Lawrence Berkeley National Laboratory (although it's a little bit dated now, having been most recently updated in 2015 I believe).

It is very easy to use and comprehensive. 

Later that evening my wife noticed they had a total of 8 people at the house around 8pm, she sent them a message reminding them of the covid rules as well as our #1 house rule stating "Any un-authorized guests on the premises will force the cancelation of the booking immediately".

So find your market which you know like the back of your hand or have friends/family/colleagues who know a market and start looking there.If you're going out of state I recommend reading the Long Distance Real Estate Investing book by David Greene and identifying a market with this spreadsheet (FYI I'm not the author, but found it very useful!).