I have a suggestion about the missing patronymic, perhaps it is hidden
in the family name ZABAWNY, in Polish it mean : Funny,hilarious,
amusing,laughing and more.....
The bibicale Hebrew name Ytzchak (Issac as yiddish name) meaning is
the same (+-) as in English and Polish.
Perhaps the took this patronymic name and used it as family name.
But ,please it only a suggestion of me.