Vowing to never let that happen again, I've indulged (probably too much) in REI education.

I've read a few books and I have the basic education down, but I'd like to get my feet wet with REI.

The goal with paying it off would be to jump the mental hurdle of owning a property free and clear, start an LLC and transfer the title into that LLC, and then to have a property that we can HELOC against in order to have the flexibility to make cash offers so that we can begin making LLC purchases more easily rather than titling in our own names.I'm certain that plenty here would advise to continue rolling the money into new properties, rather than to pay one down, since owning the house free and clear would provide about half the cash flow that we could get from down payments on two new properties, however my wife (in particular) and I both like the idea of simply owning one property outright and then using the above strategy moving forward. 

I currently gross around $120K per year and plan to maintain this income through the first many years of my REI journey.So far: I’m educating myself on the process of REI by reading books, following the forums, attending webinars, etc.

If you are new to REI as a whole, I would say that you should continue getting educated.

For solid education, Papersourceuniversity.com has free education.

The best way to get started is to educate yourself, in-depth.

3) Will I continue paying same property tax on primary and new assessed property tax on the "new" ADU ?

I always wanted to ask her why she felt like a couple of months of construction was worse than continuing to let the home be a drug house and neighborhood eyesore...

Once I sold the collateral at auction to take it over he continued to threaten and intimidate the tenants to pay him rent.