You don't until both your interests are aligned and this usually takes time and even that isn't foolproof. 5. 

Look locally and search Zillow, believe it or not, the pre-foreclosure designation that you see on the site on a property means that a person is delinquent on their mortgate payment (granted no site is 100% fool proof). some of the dialer services like Red-x or Mojo may offer you lists and contact info as well, but I find that the phone numbers they provide often don't work

Won't be foolproof because streets can be good on one block and bad on another.

No screening system is foolproof.

A professional property management firm that does leasing generally can read people pretty well and cut down on those chances of bad tenants (it's not foolproof though, and would recommend some reserves after you land a property in case there are issues). 

Which one would ensure (the most foolproof way) that the tenant vacates?

In our market here in SLO you’ve got to be creative to make deals work, the 70% rule is a good base but it’s not fool proof and it always depends on the property.

These aren't all foolproof of course, but basically the people that go through life events and become distressed sellers actually reach out to you and only - being the main difference.Again, I need to play within the guidelines on here and I also like to genuinely help on here so if you'd want to at least learn a little more let me know!

It's fairly fool proof.

That's in part a result of Series LLCs being complicated to set up and thus more expensive and thus more money that an attorney can charge you, part a result of it being a shiny new toy that every attorney wants to try out and set up, and part a result of attorneys wanting to provide maximum, duplicative, redundant protections for their clients (no lawyer wants to be the one who assures their client that their LLC is foolproof or to say that their proposed course of action will be fine only to later watch that client lose their business, home, car, coin collection, etc.).