I've looked at many units/homes where the place was a disaster (and the tenant knew I was coming.)Talk to the owner (or agent) and get a copy of the lease.

However, the age and thus accuracy of these records offered by third parties online should always be questioned since their data is copied from the source.Finally, there is another type of lien record which is not available at the county courthouse nor is it available online! 

This might be sufficient before putting in an offer and during DD, you might want to get copies of actual leases, detailed information about tenants, Estoppel Certificates, survey, title policy, etc. 

Highly suggest getting a copy of Tom's book tax free wealth.

Ergo, the advertisement copy worked. 

You can request a copy of the final inspection report for confirmation from the city.

I am writing contracts for each scope of work, printing or pdfings, signing, savings, sending signed copies, writing change orders and doing the whole process over again.

Are there any specific forms/applications for them to fill out to take to their creditors so they provide the information freely? 

From the interactions I already have had and the information that is freely available, I know I am in the right place to ask an important question:What is the one piece of advice you would offer for my first apartment purchase (16+ units)?

This was only found out after I was given copies of the leases.