The children of your husband's siblings are your nieces or nephews. Their children are your great-nieces or great-nephews.
you call her your daughter's husband's sister
sisters in law
She is your sister-in-law.
Your sister-in-law.
your brother-in-law :)
Brother-in-law.
You would call your husband's younger brother a brother-in-law.
Phillipp uncle
There is no specific word for the husband of your wife's sister. If you need a phrase, call him your "sister-in-law's husband."
either your niece's husband, or your nephew, or your nephew in law, etc
Jijaji- brother in law