You and the granddaughter of your great grandmother's first cousin are third cousins, once removed.
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.
They would be your parent's first cousins once removed. So they would be your first cousins twice removed. They are two generations away from you so they are twice removed.
Your children and your husband's niece are first cousins. There is a difference of one generation between them. That makes them first cousins once removed.
It could be one of two answers. They could be third cousins. Or they could a first cousins four times removed.
Your brothers granddaughter is your grandniece.
Your grandmother's brother is your parent's uncle. The uncle's child would be your parents first cousin. You would be second cousins.
Your great great niece is the granddaughter of your niece or nephew. Your daughter and your niece or nephew are first cousins. Your daughter and your great great niece are first cousins, twice removed.
She would be your first cousin, twice removed. "Twice removed" means that the relative has two of the same great-grandparents as you.
Your son and your sisters child are first cousins. The granddaughter is out of synch by a generation. That will make them first cousins once removed.
Your daughter and your sister's son are first cousins to each other. Your sister's son's daughter (her granddaughter) and your daughter are first cousins, once removed.
If you and someone else have grandmothers who were First Cousins, the parents of those grandmothers were siblings and you and someone else have great-great-grandparents in common. Therefore you and someone else are Third Cousins.
Your granddaughter and your first cousin are first cousins, twice removed, to each other.