Your niece in law.
Let's see if we can unravel this. Your sister's husband's father's brother is your sister's husband's uncle. The uncle's daughter is your sister's husband's cousin. There is no relationship to your sister, unless your sister wants to call her a cousin-in-law. To break it down to its simplest terms: She is your brother-in-law's cousin and no relationship to you.
None.Your daughter's husband is your son-in-law and his sister is your daughter's sister-in-law. But the English language does not consider you to be related to your daughter's husband's sister
Your sister-in-law's husband may be your brother. If so then the brother-in-law is either your husband, in which case the daughter is your daughter; or the brother-in-law is your brother, so the daughter is your niece or the brother-in-law is the brother of another sibling's spouse, in which case the daughter is still your niece If your sister-in-law's husband is not your brother, then he is not related to you and his brother-in-law's daughter is not related to you.
Your sister's daughter is your niece. Your niece's husband is not related to you.
Your niece in-law, or your niece by marriage.
Since your sister's husband's daughter is usually your sister's daughter, you are her aunt or uncle. If the husband's daughter is from a prior marriage (before he married your sister) then the daughter is not related to you. However, if the daughter is young, her father may have her call you and treat you as an aunt or uncle.
None. She is your daughter's sister -in-law.
She is your sister-in-law.
If he is your brother in law then his sister is your sister in law. So your sister in law's daughter would be your niece.
sister in law
Your mother's sister-in-law is either the wife of her brother (your uncle), or your father's sister (your aunt). The niece of your uncle's wife is not related to you, unless she is you, your sister, or a girl cousin who is the daughter of another of your mother's brothers or sisters. The niece of your father's sister is you, your sister, or the daughter of another of your father's brother's or sisters. If your father's sister is married, she may have nieces who are the daughters of her husband's brothers or sisters. Those nieces are not related to you.
Your daughter's aunt is your sister, or your spouse's sister Your sister's husband is your daughter's uncle Their daughter is your daughter's first cousin (and your niece) Her sister is also your daughter's first cousin (and your niece) So, the answer is: her first cousin, and your niece.