As in two or three years living with this person whose shall we say lifestyle is so uncomfortable to you???

Personally, I would do the research first, get all the answers confirmed and then look into the market to do a deal.  

As a non owner occupied property minimum down payments are:Conventional (single family) - 15%Conventional (multifamily 2-4 units) - 20%Non-QM (1-4 units) - 20%Certain Non-QM DSCR products allow the use of gifted funds for your down payment. 

If one person stops paying and it's tolerated, It's more likely to spread within the house.

Great write up, choose your poison, but different products are suited to different situations!

@Joseph MuleroTo boost your rent plan and make more money in the medium-length rent market, think about these steps: slowly add furniture to the new place while you stay in your current home, pick cheap furniture, use a credit card with good terms, look into loan options like personal loans or home equity credit lines, try out the market by listing the place with few furniture pieces, aim for easy-to-change furniture for flexibility, and talk to pros like real estate agents or home decorators.

I'm personally looking at the 2-4 space right now as I think there should be good opportunity there to make the numbers work in high-value markets

Q3: My personal rentals have not, but I bought in Lawton, OK because that was my duty station.

The person you mentioned has no formal credit background.

The only PITIA paid from personal account is for a personal residence.