I'm not sure how much those questions matter to the school. I think its just a way to get to know you a little better. I have a feeling those questions won't hurt an applicant, but have the potential to help an applicant who is disadvantaged, but since I'm not adcomm, I don't know for sure.
My family looks a bit like yours.
My parents were uneducated, in fact, my father only went to school through 9th grade.
My brother is a dentist.
I know it didn't hurt me. It may have even helped me that my parents were uneducated - maybe placed me in a disadvantaged category, even though I didn't actually check the disadvantaged box on the application. The fact that I was slightly disadvantaged may have filled in some holes in my application. (Lack of clinical experience and research, taking a few years after college to decide to come to medicine, slightly lower MCAT).