In almost every family I know, they would be called grandmother. Even though there may not be an actual relationship. In many families, she would be referred to by her first name or as grandfather's wife.
Your great great grandfather.
Your father's grandfather is your great grandfather.
Your great grandfather
Your great grandfather
Your great great grandfather.
Mother in-law
Your grandfather's brother is your great uncle.
Your father's grandfather is your great grandfather.
Sugar Daddy
You call him grandfather.
He would be your great, great grandfather, but you could call him whatever endearing name you and he prefer -- Granddad, Papa, Grandpa, etc.
Your grandfather's brother is your Great Uncle.