In all the world, Kostelnyk (Kostelnyk , Костельник ) is an extremely rare unknown gender first name. Much more prevalently, Kostelnyk is the last name as well as the forename.
Костелник, and Костелнык
Eli, Mark, Olga, Peter, David, Andrew, and Paytyn
, Костельник 
) is an extremely rare unknown gender first name. Much more prevalently, Kostelnyk is the last name as well as the forename.