Kajzer, Sztefko, Balcerzak, Ldziarstek, Kowalczyk: Kozy, Warszawa (Warsaw) relatives

Looking for relatives from Poland. Grandfathers name was Jan Kajzer. He was 1 of 10 children. Only one to come to USA in 1920 that we know of. Working on a family tree. My dad used to write to relatives in Kozy and Warazawa. They were his sisters that were married and had different last names. Not sure if all sisters got married, had 5 brothers 4 sisters. Nmes looking for Kajzer, Sztefko, Balcerzak, Ldziarstek, Kowalczyk. From old letters I think I spelled their names right???

All names but Ldziarstek looks OK and exist in Poland. Ldziarstek seems wrong, maybe Zdziarstek/Dziarstek?

Check maybe for above names in popular social media sites like Facebook and Nasza Klasa (Polish equivalent of FB) - some relatives should live here in Poland.

Maybe it was:
£ODZIAREK: possibly a patronymic from łodziarz (boatman, boat-builder), hence the boatman's son.
Without the slash through the L it woudl be Lodziarerk, son of the lodziarz (iceman), except no-one in Poland uses it at present.

KAJZER: this is the Polish respelling of the German word Kaiser (emperor). As a surname it probably originated as a toponymic tag to identify someone from the tiny hamlet of Kajzerówka in the Mazowsze region's county (powiat) Kozienice.