Rabbi Illana is AMAZING! Within 20 minutes of emailing the photographs of the headstones to her, she had emailed back the translations. To know my Great Grandfather's full Hebrew name is totally blowing my mind. So the man I knew of as simply Simcha is actually Simchah Yehudah, the Cohen.
I asked the Rabbi what "The Cohen" meant and here was her explanation: The Cohen means, hereditarily they are part of the priesthood that existed in ancient Israel. The Cohanim and Liviim (the Cohens and Levites) ran the Temple in Jerusalem, saw to the sacrifices, offerings and other things. For many modern Jews, this is no longer an issue. For those who are waiting for the Temple to be rebuilt and sacrifices resumed, they want to keep track of who was part of which tribe.
So, now I know that my Great Uncle Sandor found it extremely important to have "The Cohen" inscribed on the headstones of Simchah's children. Now if I can just track down where Simchah and Great Grandma Pepi are buried. If I can find Pepi's headstone then I will be able to find her Hebrew name and the name of her father which would be INSANE!