I'm trying to get my characters right and not offend anyone

Hi everyone!

I'm writing a historical fiction novel that has 14 characters from varying backgrounds. While I've been doing plenty of research through books, documentaries, and academic sources, I'd really love to hear from people with lived experience or family connections to these cultures. I'm not looking for anyone to write my book for me. I just want to make sure I'm portraying my characters respectfully and authentically. Some of my characters come from the following backgrounds. Since it is historical fiction set in the 1920's going into the 30's im sure most if not all info won't be first hand thats fine I just want to get as close tonthe source material as possible.

Lakota (Sioux) (boarding school history, traditions, language, family life, spirituality)

Black Americans (primarily from the Midwest and South during the 1930s)

Korean (pre-division Korea and the Japanese occupation)

Japanese

Polynesian/Samoan

South Asian (Hyderabad and Rajasthan)

German (especially families living under the rise of Nazi Germany)

Polish Jewish (life before and during the Holocaust)

Irish American (working-class families in the early 1900s)

Italian American

Afro-Latino / Afro-Caribbean (still refining this character's heritage ig it will depend on who answers first)

I'm especially interested in things you don't usually find in history books:

Family traditions

Food

Humor

Nicknames

Childhood games

Superstitions

Sayings your grandparents used

Things your family did that "everyone just knew"

Everyday life before modern technology

Stories passed down through your family

I'm not expecting anyone to do extensive research for me, and I completely understand if some topics are difficult or personal. Even small details can make a character feel much more authentic.

If you're comfortable sharing, I'd love to hear from you here or through a DM and if you'rein the indy area id love to sit down and talk face to face...in a public place of course.

Thank you so much!