@Mia Gregory I cant speak specifically to Missouri law. Tax sales vary tremendously by state.
However in general if you complete a tax lien foreclosure you wipe out any other liens and ownership interest against the property. I'm sure you heard how you can buy houses "for pennies on the dollar" just pay the taxes and the house can be yours. the reality is while that is possible the competition dosesn't allow it to happen. Tax sale auctions can be very competitive and there is risk involved.
Nationally it is said that about 95% of the property owners will redeem and you only get the interest. But the 5% that go to foreclosure are often homes in very poor condition or sometimes worthless strips of vacant land.
I never understand why people say you need to do a title searh first. If you foreclose the attorney will do a title search and serve all parties that have an interest. Tax sale cleans up the title by removing all the clouds and junk attached.
Now knowing that the owner is dead or some other factor like the property is boarded up, may increase your chance of getting the property. But you never know, the estate or heirs will have to be served and they may redeem.
I suggest you spend some time to learn the rules in your state/county. Often the county website will have good information about heir tax sales and the process.
I have done well with tax sale investing but like I said in the beginning the laws vary tremendously. You need to know how the laws in your state. good luck