Now we have uncovered the fact that they are not using our furnished lease, providing us tenants with criminals records and worse, and collecting late fees from tenants but not crediting them to us.Recently I partnered on a few houses with a friend of mine and he is now like a terrier on a mouse - once he found an single issue he went wild investigating.

We fired one of our property managers a few weeks ago and are now hearing about issues of negligence and possible criminal activity with missing tenant payments and/or not properly handling security deposits.  

Pay for those credit/criminal/eviction/employment checks.  

Whether you are a Section 8 property or not, you still want to get tenants who will pay rent and not damage your property, or cook meth in it, etc.If the only people who are willing to live in a property are criminals or undesirables, then you will have problems.So, no, not any property will be a good investment.  

I emailed him a list of all of the terms and he said the only thing this company won't do is the criminal background check.

You only need to prove your case to 51%, not "beyond all reasonable doubt" like a criminal case.

@Robert Ablorh If the collections were medical and closed, and their current credit, criminal, and eviction histories as well as their rental references are good they sound like a decent pick to me.  

On background/credit search, they both have good credit history but they both also have criminal background.

It's fairly common to require a co-signer for college students though since their income isn't going to meet your criteria and you then run their parents credit and use that as your basis for qualification.For prior evictions and criminal, those are still extremely important to run on the students.It's also quite common for there to be multiple students sharing a house, so handling split-responsibility for the payments is also another very common thing to do in college housing.

You also need to know if either has been evicted or has a criminal record.