Regarding Weyland. One thing I realized was Miss Vickers' line to David asking "Did anyone die?" She really was asking, "Did Peter Weyland die?"
Which really begs the question.... why was she THERE? If she wanted to control the company, you know, assume the throne, wouldn't him LEAVING be the perfect time to do that?
Instead she left on a 5 year (?) voyage to some remote planet, while OTHERS were running her Daddy's company... a perfect time for THEM to stage a coup.
Vickers.... as dumb as the rest of the characters.