I then modify those numbers based on the buyer's preferred down payment/return hurdles.

I wouldn't want someone to hold back, I prefer honesty and straight talk. 

While you can have a checklist of income, credit score, criminal background, landlord reference, etc, to me the bigger tell of good versus less than good tenants came from all the interactions prior to leasing.  

With Appfolio you could select your preferred vendors. 

I’m Norwegian, I live in Dubai but I still prefer to invest in USA. 

Most don't use them all; some fill them themselves with their preferred coffee or tea.  

I have no particular area that I'd like to start with or focus on, but probably prefer somewhere in the south of the US due to my strong aversion of winter.

Through preferred rates and quarterly cash flow, I strive to create multiple revenue streams for my investors.

If the other party is a lifestyle buyer, he's going to prefer to own his own property rather than have an investment he/she can't control.

Use a property manager for out-of-state properties or if you prefer a hands-off approach.