One roommate out of three tenants on a joint + several lease has descended into hardcore drug use, bringing domestic disturbances and unwanted guests as well as drug use on the property according to the other roommates.

For instance, some gentrifying areas actually see population loss as multifamily buildings are converted into SFHs and apartments that used to house entire families are rehabbed and rented to a couple roommates. 

That's a bit more that $2900 per month.Expenses:-$1400 -- rent (with roommate, admittedly this situation will change)-$350 -- electric, gas, phones, internet, car insurance-$500 -- health insurance-$200 -- groceriesTotal: $2450That leaves a net of $450 for luxurious expenses and a safety net for "**** happens" - car repairs, vet bills, medical bills, etc.Clearly doable, while living in the most expensive place in the world and living like a king compared to 99% of people on Earth and 99% of people who have ever lived.

Ensue fight about which roommate is responsible for said repairs. 

I want to get a great deal with my first purchase (live in and rent to room mates) and keep my cash using an FHA or 203 loan and I’m not sure if people do this or not with off market deals

Mortgage fraud will get you a room, but you have no choice about the roommate.

The loan essentially cost us nothing (except for dealing with a roommate), and we had an extra $300 in our pocket every month. 

I have been living with roommates in rentals and have become motivated to do the same but actually own the place. 

When I bought my primary residence I was in the same situation - I started looking in May of 2012 and my lease was up at the end September (my roommate was staying but I was leaving and his relatives were supposed to move in). 

I knew that I wanted to buy a duplex when I graduated from college so I could have tenants pay my mortgage, and roommates help with mortgage and utilities.