Genealogical Research uncovers an adoption dilemma

While conducting genealogical research on my ancestor, I also conduct research on their siblings as well as the siblings' descendants. At times researching the siblings and their descendants have helped me uncover leads and information about my own direct ancestors. It has also helped me with finding possible candidates for my DNA project.

Yet a new twist in my genealogical research has recently uncovered a very probable adoption of my 'first cousin twice removed' to another family. From the research that I have conducted on a Great Grandmother, I've uncovered that her brother got married to a young lady and fathered three children in this union. I have the marriage certificate of this union as well as a census document of the married couple and their first child. Five years after been listed in the census, his wife as well as his first born daughter dies for which I have their death certificates. At this point, there was no initial knowledge that any further children except the very first one exist. While conducting further research of the now deceased wife in this marriage, I uncovered that in the very next census her brother was taking care of two children listed as adopted and also with the surname of which his now deceased sister had married into (my Great Grandmother and her brother's surname). Just three years after this census that shows the now adopted children, the head of the household (the children's uncle) dies. It appears that his wife could not for whatever reason keep the adopted children. Through another resource, I've uncovered that the girl of the two children was residing in another family's home in a different county, initially using her original surname. This resource also gives a connection to her brother with whom she was now separated from to live in this new household.

On continued research of this little girl, she went from using her original family surname to that of the adopted family which is understandable. Her SS-5 form, obituary as well as her death certificate has her adopted parents as her original parents. I have since uncovered that she had married and had at least one child. Upon further research I have located her descendants. I am unsure if she was aware of her adoption as well as if her descendants.

Having stated all of the above information, to which I hope was understandable, I am not sure if or how to go about approaching the unacquainted descendants of this first cousin twice removed. Any suggestion and or thoughts are greatly appreciated.