Have you done a criminal background check? 

If the income, employment, criminal history, and communication is good I don't see a problem.

As long as your landlord tenant laws, don't have any certain exemptions, you can collect first come first serve, or collect them all and choose which one you want based on their income, Credit, rental history, eviction, criminal etc... 

In some cases with professional administration you also have access to much deeper vetting of the sponsor that will include personal background checks covering things like bankruptcy, judgements, litigation, criminal history, and other red flags related to a sponsor that you would want to avoid.If that is not available, another approach is to talk to investors who have had an experience with the sponsor already.

I Use Keycheck for criminal, eviction and credit score background check.

They are total white collar criminals, living on yachts, and sipping martinis on everyone else's dime. 

There are multiple layers of criminal activity.

Clean criminal history and no evictions. 3x the monthly rent in income.  

I think I saw a discussion that was saying that criminal record might become something that you can't deny an application based on.

Usually a big difference in terms of what type of fence can be installed in the front of the home as compared to rear.