Earlier this year, I reached out to Schlun & Elseven, a German law firm that specializes in cases of citizenship proceedings to petition my case. After some initial information gathering, it was determined that I was indeed eligible through my great-grandpa, Paul Erdmann, since he had not naturalized as a citizen of the United States (a disqualifier), despite him filing for citizenship status after his immigration. This was evidenced by his filings in the 1940 and 1950 US Census records, in which he filed as an alien and non-citizen respectively. Subsequently, my mother and grandmother did not disqualify themselves and were also technically eligible, since they were born in the United States and did not need to naturalize.
The citizenship filing is on the basis of a German law that was passed after the events of World War II, in which individuals who were forced to flee Germany or otherwise left, and their descendants, would be eligible for German citizenship if their ancestors were German citizens and through their lineage to the last ancestor, none disqualified themselves (through naturalization, foreign military service, child out of wedlock, among others).
The Search for Information
While gathering information for the initial filing, I have discovered a lot more about my immediate ancestry, particularly of my grandmother, grandfather, and great-grandfather.