The answers I received >from people ran the gamut:
The Hebrew name is either Aryeh, Judah, Lev, or Levi.
Leivik is either a diminutive of the Hebrew "Levi" or the Yiddish
"Leib" or "Lev."
Now, the decision as to what name to use has to be made.
Rochelle Gershenow

Dear Rochelle:

If I may offer a suggestion regarding the stone:

First off, you can forget Levi altogether (that was a bumsteer based
on an error) and stick with the other three names. Your father
almost certainly received two of the following at his circumcision
ceremony: Aryeh, Judah, Lev.
Since double-barrelled names are the norm for Eastern European Jewry,
you could pick any two of them, as follows:

(1) Yehudah-Aryeh (the traditional original all-Hebrew version)
(2) Juda-Leib (a very common Hebrew-Yiddish combination among East
European Jews).
(3) Aryeh-Leib (the Hebrew and Yiddish words for "Lion" -- another
common combination)

My husband's father was known as Leo in Vienna, but Polish birth
documents called him Lew (pronounced Lev). So we were virtually
certain that my husband's father -- who had been born into a
Yiddish-speaking family -- must have been named Juda-Leib at his
bris. In naming our firstborn for him, we selected Yehudah Aryeh
because we preferred the pure Hebrew original version. But since you
know that your dad was known as "Leibl" and/or "Leivik", you might
wish to preserve that by choosing either Aryeh-Lev or Yehudah Lev
as the Hebrew name on his stone.

Best wishes,

Judith Romney Wegner