For mortgage debt, the following additional requirements must be met:the party making the payments is obligated on the mortgage debt,there are no delinquencies in the most recent 12 months, andthe borrower is not using rental income from the applicable property to qualify.

Average Houses are around 600k where I am living which means if I put 20% down I’ll be looking at a payment around 4500$.

I get a judgement and execution and contact the local constable.After a month or two, if they don't pay they get summonsed to a payment hearing.If they don't show, now the constable threatens to arrest them if they don't pay.Just collected 5k judgement doing this.Good luck

The cons - very hard to cash flow off the bat, especially with a low down payment and...

Another option is to get an interest only loan, which reduces the payment amount and thus allows for more cashflow.

., if the housemate who’s leaving was covering 75% of your mortgage payment, that could be a major problem…but if they were only covering a small portion of the mortgage and/or they’re easily replaceable, it might not be much of an issue).Moderately important: anticipate and manage your relationship with the housemate tenants.

Once you do, begin the termination for non-payment process that your lease (hopefully) spells out.   

But multiple credit cars, car payment, rent is a no go.I've had a few tenants that went thru foreclosure when the market crashed, and want to rebuild.

If they truly had your best interests at heart, they would defer the payments until you made a profit. 

This will have a significant impact on your loans, especially on lower balance loans or loans with low payments.