Your aunt-in-law's parents would be your grandparent-in-laws.
Your Aunt's first cousin may be your second cousin, onve removed or may be no relation to you at all.
The daughter of your aunt is your first cousin. The daughter of your great aunt is your first cousin, once removed.
Your Aunt/Uncle's child.
Your Aunt's first cousin may be your second cousin, onve removed or may be no relation to you at all.
Your Aunt's niece is you (if you are female), your sister, or your First Cousin.
Your aunt's daughter is your first cousin.
Your great aunt's son is first cousin to one of your parents, and first cousin once removed to you.
Your great aunt's son is first cousin to one of your parents, and first cousin once removed to you.
aunt or uncle;) depends on the gender
No, cousin and great aunt are very different relationships. Your great aunt is the sister of your grandfather or grandmother. Your first cousin is the child of your aunt or uncle. (Your aunt and uncle are sister and brother of one of your parents.)
2nd cousin or 2nd cousin in law.
There is no relation between you and your grandmother's cousin-in-law's grandson.