Below is a ketuba for a bride name Chaya bat Yehuda, and Yehuda's father is shown as Rav Tzvi HaLevy.
I know for a fact from people who knew him and from multiple original source documents including other ketubas and birth certificates that Yehuda's father (my great-grandfather) was named Mordechai, known as Mochi Iancu in Romania. They adopted the surname Schwartz. I also know that Mordechai was no Levi, since his son was my grandfather and we went to shul together 100s of times. Nor was anyone (relevant) adopted.
Since Zvi HaLevy was not the name of her grandfather, I'm wondering if perhaps it might be a symbolic or mystical name, or perhaps some other explanation.