During due diligence:  get copies of current leases, lease amendments,       exhibits, rent receipt details (proof of tenant's paying timely), deposits       held, etc. 

I want to build a freemium version called SyndicateStreet (open to a better name).

Instead use your OWN logic and data and you will soon see I am actually right (if my numbers and reliable predictable repeatable results didn't already make this obvious.Motivated sellers don't exhibit those situations, as 90+% of my organic (meaning REAL, actually wanting to sell) leads do not come from those categories.

I wouldn't.My last investment property was basically ruined by my last tenant, but I know most of that fault was mine -- I had hardwood floors, I let them bring their pit-mix in because I was desperate for a tenant, they barely made the financial requirement, and started exhibiting weird behavior about 1.5 years in.

Not deface, damage, impair, or remove any property, facilities, fixtures, wiring, equipment, and appliances; not install TV/radio antennas, decorations, not other equipment without landlord/agent approval; not exhibit any signs, advertisements, notices, or other lettering.

That could have been exhibit A for your small claims case, or for your criminal complaint. 

You look for potential vacancy which can be exhibited by broken windows or mail piles.

Major concerts, Broadway and symphony performances, extensive permanent collections and traveling exhibitions contribute to a wonderful way of life.

(a) A landlord may enter the dwelling unit only in thefollowing cases:(1) In case of emergency.(2) To make necessary or agreed repairs, decorations, alterationsor improvements, supply necessary or agreed services, or exhibit thedwelling unit to prospective or actual purchasers, mortgagees,tenants, workers, or contractors or to make an inspection pursuant tosubdivision (f) of Section 1950.5.(3) When the tenant has abandoned or surrendered the premises.(4) Pursuant to court order.

To start, was this a good tenant that is now exhibiting out of character behavior or is this a habitual late/non payer?