Thank goodness this never happened to me cause my parents were good parents, it’s just as much the childrens home as the parents and children should be allowed to say “I don’t feel comfortable with another man or woman living hear” Its the parents responsibility to make sure their children are comfortable and feel safe around a new adult. The parent should plan a public meet and greet parent, child, step and after each one the children should have the right to say no more and it end there.
An adult does not need a minors consent to do anything.
It’s the other way around. Be the parent. Do not look to a child for answers you’re expected to already have.
There is no argument you will find that trumps what I am telling you.