Your grandfather's sister is your great aunt.
Lets explain this step by step as so many people get all this genealogy family stuff mixed up 1.Your Grandfathers niece(this would have to be your grandfathers brother(your great uncle),or sister(your great aunts)daughter to be your grandfathers niece. 2. This niece of your Grandfather would be the first cousin to your mother or father, 3. This niece would be your "SECOND COUSIN"
Most likely they would not be related to you
Grandmother
Im not to sure, but I would have to say your Aunt.
What is my godfathers niece to me
cousin
Your niece's brother is your nephew.
Your wife's niece is also your niece, so you are her uncle.
For clarity, lets call your great great grandfather's niece "the niece". The relationship sequence: (1) The niece is the daughter of your great great grandfather's sibling (2) The niece is a 1st cousin of one of your great grandparents (3) The niece is a 1st cousin once removed of one of your grandparents (4) The niece is a 1st cousin twice removed of one of your parents (5) The niece is your 1st cousin three times removed
For clarity, lets call your great great grandfather's niece "the niece". The relationship sequence: (1) The niece is the daughter of your great great grandfather's sibling (2) The niece is a 1st cousin of one of your great grandparents (3) The niece is a 1st cousin once removed of one of your grandparents (4) The niece is a 1st cousin twice removed of one of your parents (5) The niece is your 1st cousin three times removed
Your son and your niece are first cousins.
Could be your daughter or your niece.
3rd cousin