I owned one for 13 years but it was a STR for only a couple of years prior and the other for 7 years and was always a STR.  

One thing I would add here is to check prior landlord references, not just from their current one.

But without the experience, knowledge and capital (actually CREDIT CAPACITY) I accumulated the prior 2 + years, this transaction would not have been possible.

Are you not necessarily denying him based on screening criteria - Some landlords make it a requirement to view the property prior to letting the applicant apply.

Do you provide move in and move out reports How many pictures do you take of the property prior to tenant moves in and after the tenant moves outDo you get weekly reports when the property is vacant what prospective tenants are saying about your homeDo you provide monthly newsletters to your tenantsDo you hold investor education classes to help me become a better investorDo you have single point portfolio based management services?

I bought a business where the prior owner had it in an S-Corp, the S-Corp and he was sued personally for three million.

The home was a rental property prior and had been sitting.

I get into contract in my operating company and then assign the contract to the new LLC prior to closing.  

I want to make sure this is something I have no doubts about prior to jumping in.

They are grandfathered in, the property was built prior to those standards.