Your step-father's cousin is not related to you because you have no ancestors in common. However, if your step-father came into your life while you were very young, you may e treating him as your father and his cousins as yours. In that case you might consider that if he was your biological father, his first cousin would be your first cousin, once removed.
Your cousin's cousin could either be your cousin or no relation at all.
He is of relation as a cousin-in-law.
Well, your cousin's brother is also your cousin, and a cousin's son is also your cousin.
Your cousin. You are that person's second cousin.
Your cousin-in-law.
Second cousin
They are your cousin-in-law.
Cousin in Law
still your cousin
Your Aunt's first cousin may be your second cousin, onve removed or may be no relation to you at all.
Your Aunt's first cousin may be your second cousin, onve removed or may be no relation to you at all.
There is no relation between you and your grandmother's cousin-in-law's grandson.