I believe the 4 witnesses only work if they are all men. Correct me if I'm wrong.
yes u are right. in hudood cases the witnesses should be men, muslim,adult and rigteous. and they should have seen the sin commited with their own eyes. and should all bear witness in the court at the same time/session.. if any of these conditions is missing, hadd punishment can not be imposed.
this is a very very strict criteria and almost impossible to meet. this is the sole reason that not a single person had been punished with hadd on witness in the period of the Holy Prophet (p.b.u.h).all the punishments had been based on confession