You would be 2nd cousins, assuming that the brother's wife's granddaughter is also the brother's granddaughter. If the granddaughter is not the granddaughter of the brother, there is no relationship.
Your 1st cousin's granddaughter would be your daughter's niece.
they would be cousins.
Your grandson and your sister's grandson are second cousins to each other.
Your niece and your child are first cousins. There is a difference on one generation between the two. That would make them first cousins once removed.
The granddaughter is the niece's first cousin once removed.
Your first cousin's daughter is first cousin once removed to your grandson, and he to her. Your second cousin's daughter is second cousin once removed to your grandson, and he to her.
Your son and your nephew are first cousins to each other. Their daughters are second cousins to each other.
they would be first cousins once removed. this is because the grandchild's parent would be your son's first cousin and because its the cousin's child, its once removed
They would be your second cousin. Your great aunt is the sister of one of your grandparents. Your parents and the granddaughter's parents are first cousins.
First cousins once removed. Your child and your nephew are first cousins and there is one generation difference.
Your niece and your son or daughter are first cousins. That would make your niece and your grandchild first cousins once removed. Your niece's child and your grandchild are second cousins.