All properties are eligible for a cost segregation study as long as they are investment properties.

You will have two separate K-1s as you are each individual owners.  

So, your property must be secured with deterrents to hopefully stop this from happening - but, it's impossible to guarantee security.

I'm interested in selling them owner finance.

If you decide to sell and find an investment property with a greater cash flow potential.A 1031 exchange would allow you to indefinitely all of the tax and use it to your advantage to reinvest into larger nicer property/properties.

Haven't had much success with people I've used in the past for other properties  Thanks

I've invested in 6 properties and counting with them.

Depending on the amount owed I might pay it off after I’m under contract to do a property inspection and ask for the money back at closing.

For several reasons (property taxes, politics), I would prefer to begin real estate investing somewhere other than locally. 

Lots of these owners have had these properties for a long time.