Me for instance I spend over $1M per year finding these people.

I'm not an attorney or accountant, so I highly recommend you consult with both or use someone who does both: accounting and legal, like Mark Kohler for instance. 

Your verbiage actually makes it a grey area open for interpretation for a judge in your instance. 

For instance, if someone else purchased the property even with the clouded title, could I take legal action?

For instance, you might be buying a legal triplex that has four or five actual units.How hard would it be to get such a property rezoned for the extra units in Nassau county (town of Hempstead)?

If it's as advertised seems like a great opportunity.Or if there is truly that much equity in the house just purchase outright from her at a price she deems is fair etc -- multiple multiple ways to skin a cat or in this instance solve a problem.  

However, if you have a 10-year for instance, you will pay more in principle than you can deduct in taxes by a significant amount.

For instance, if there's a duplex in your area that needs huge rehab and nobody is interested in, then come up with an offer that will make it attractive to you and take action. 

For instance, you may want to have one half of the lights upstairs on one circuit and the other half of the house upstairs on another circuit.

for instance I built a fence and some pergolas last summer and I understand that is something that is depreciated over 15 years.