Your wife's brother's daughter is her niece and your wife is her niece's aunt. Although you have no genetic relationship to your wife's niece, by convention your wife's niece is considered to be your niece and you are her uncle.
granddaughter
Your brother's daughter is your niece..and you are her AUNT.
Great Niece.
YES
Which One ? Hailie Jade Scott (Biological Daughter), Is 13. 25/12/95. Alaina Marie Scott, (His ex-Wifes, Twins Daughter. His Niece. But He Adopted Her) Is 16. 3/5/93 Whitney Laine Scott (His ex-Wifes Daughter From A Different Relationship Who He Cares For) Is 7 16/4/02 :]
You are their aunt or aunt by marriage.
First cousins twice removed.
That would be her great uncle I suppose. Common sense.
Your younger brother's wife's sister's daughter would be your son's cousin.
Your brother would be your son's daughter's great uncle and your son's daughter would be your brothers great niece! Hopefully that makes sense :)
his ex wifes twins daughter
Your sister's daughter is your niece and you are her aunt (if you are a woman) or her uncle (if you are a man).