Shadow Man
What a refreshing change for an relevant question to be asked about women's bodies. Recently some men on this site have been condemning the questions about women's bodies. Their prudishness? has led them to complain about appropriate questions asked by women. You on the other hand in your unsubtle attempt to denigrate women, have inadvertently asked an interesting question.
As someone who has never had children, I can not comment on
1- 3
4) genitalia as it is external will not be changed by child birth only gravity! The vagina, cervix and uterus will be definitely changed by pregnancy and childbirth, but without a proper investigation by someone trained, no it will not be detectable.
As for nipples, the development of dark aureoles is often associated with pregnancy but can occur at other times as well. Seems to be one of those vagaries of life really.
You have already answered the issue of stretch marks. It would be very emabarssing for some men if these only occurred during pregnancy. They occur with significant weight change so men get them as well.