For collecting rent/applications use COZY it's free and an awesome service.

The landlords that can't collect for 6 months. 5% vacancy is 1 turnover every 20 months.

Always do a background/credit check, call their last two landlords, collect a security deposit, have a formal lease, call their employer to verify income and to get an idea of how they perform at work and be extremely clear in your standards.

You're really just assuming someone's mortgage and instead of collecting rent, you're collecting a mortgage payment for the life of the mortgage (15-30 years, unless they cash out early).Now it would depend on how much capital or access to capital you have to outlay since notes are capital intensive but in essence it's really just this: instead of using your out of pocket capital to pay down your debt, you buy debt like cashflowing mortgage note and you utilize that arbitrage to make your credit card/loan payments.

@Pete PanciFor house hacking a duplex or triplex is the best option. you live in one unit and collect rent for the other 1-2 units.

This is not any kind of rule-of-thumb, just our collected experience.

This would also allow you to collect the personal data on these inherited tenants in case of future legal action.

I would put all on one lease, but would like to collect rent together and not from three different people.How do I decide who to make the primary person responsible for paying the rent?

We firstly changed to have a management system (SiteLink) and after a year of collecting checks & chasing people about late paying we switched to everybody having a credit card and we run that card on the 1st of every month. 

Don't rehab, hold on to it a little longer to collect the cash flow, then sell when buyers and lending are more plentiful3.