That's your risk profile for legal recourse and recovery.As far as any risk profile that you will have for blight violations or quasi-criminal proceedings like property code regulations, you won't be as protected as an individual as you would be in a business entity structure. 

The percentage of time an apartment is rented as an STR is totally irrelevant (no offense everyone).

Aside from providing the basics (ie. listing tool to get the property published to 10+ major sites, scheduling tool to schedule viewings, tenant screening with comprehensive applications -- pulled reports from TransUnion, which include nationwide criminal background checks + credit checks + eviction history, digital lease creation tool, rent collection tool, and maintenance tracking tool), some services also offer your tenants additional capabilities which makes it an easier sell on your end when getting them to transition over (ie. their ability to report on-time rent payments to the credit bureaus; this can create an added incentive for making sure they pay that rent on time).

It may cost money, but it will be done right without violating any civil or criminal laws.

He has a criminal record under his belt in the last 6 months and may still be under bail.

(still aren't sure if we'll flip or hold).I am trying to structure an offer that, both, makes our investment worth the return AND isn't offensive to this retired gentleman and his wife. 

Only after we have approved them based all other criteria, can we run the criminal background check.The problem arising from this, is that many of the tenant screening services do everything at once, and usually include criminal background checks.

You get a complete credit file, criminal and financial background and sexual harrasment as well has eviction and bankrupsy check.There are many payment options.

People who have a majority of their rent/bills paid by the government are less likely to keep care of the property and are more likely to have criminal activity at/around the property.

If it is not the case, I might hew closer to James' recommendation but with a bit more tact (no offense).