Heirship of mineral rights, royalty checks, and unclaimed property?

My family has had land/mineral rights in Payne County, OK since my Great-grandfather’s brother Homsteaded there in the 1890’s. Long story short, my father just passed away in January and my family has asked me to figure out what needs to happen. I can find online where my great-granmother filed paperwork (in the 1970’s) for her shares of the mineral rights to go to my grandfather. I did find online a court document (in the 1990’s) saying that all of my grandfather’s interests go to his wife and two children. The last actual mineral deed I can find online is my great-grandmother. My aunt and father have received sporatic checks from “The Oil Wells” as long as I can remember. I’ve also looked online and there are many Oklahoma unclaimed properties for multiple of my ancestors to include ones where there portions were given/sold to another unrelated family. I’ve called the Payne county clerk and Payne County property assessor’s office, but since I live in Tennessee, this is a process that we are all completely lost on. I need details. I know we will eventually need a lawyer; however, money is a concern. How do we legally get the mineral deeds to process through the generations? How do we work the unclaimed property? How do we get the royalty checks out of my father’s name and into mine and my brother’s? Any help appreciated.