They worked at the Shotz brewery, an obvious Schlitz standin.

Hasenpfeffer is a yiddish dish, here is a video familiar to some older generations of someone who wants to eat some Hasenpfeffer

https://youtube.com/watch?v=OdXm-cb2cjQ

Why is it Hasenpfeffer Incorporated in the jump rope rhyme they are singing as they skip down the street?

Probably because at least one of the characters is supposed to be Jewish, can't remember which one, they also sing Schlemiel, Schlamazel - unsure of spelling, which are both Yiddish words, although only Schlemiel is somewhat familiar to the public.