So far we have contested the taxes every year and we have won every time. 

There's no contest in my book.3.

Private lending is a  business not a how nice a person can I be contest 

Many of the properties require significant repairs, have clouds on title, will involve contested and difficult evictions even after the auction, etc. 

I considered trying to contest it with my own comps, but everything that I have heard about that indicates that it would be a waste of time.

As a start I went online and found these estimates for a tax confirmation suit:Average total duration: Uncontested: 6–9 months Contested: 9–18+ months, depending on disputes or appeals.2.

There's no contest.

You cant just "take ownership without contest," especially if the seller fights it.

A lis pendens indicates that a foreclosure lawsuit has been filed, marking the property as legally contested and likely in preforeclosure.

I have gotten taxes reduced by contesting the value of the B-C properties.