Whatever you and they want them to be. They can be your husband's children, your children, your in-laws, some people you hate that live with you, stepmonster victims, pointless causes of martyrdom, horrific embarrassments, people that make you happy and proud, friends, people you avoid, people you like spending time with, and/or all of the above. Don't constrain yourself to unrealistic expectations or what you or someone else thinks you should be, be as nice as you can to them and to yourself. Part of that of being nice to kids is not allowing yourself to become a doormat. Best of luck to you all.
Cousin in Law
Yes, Cleopatra had two husbands, both of them were her brothers. She had four children with men who were not her husbands.
your second nephew
Well, it depends how close you are to your husbands family. If you really want to know they are cousins-in-law.
that would be your niece or if you want to be fussy then your niece in law!
They are sisters in law.
These people are not related either by blood or by law. There is no name for their relation.
Nephews and nieces
Your husband's cousin's sister is also your husband's cousin. You are not related to your husband's cousin.
Your Aunt is your children's Great Aunt.
Carrie was the adoptive mother of her widower husbands son and daughter, but she had no children of her own.
yes