Excellent Blackie thanks, that research may be the very explanation to solve my queries:
That She's simply a good actor/chameleon
It was that half-way thru the movie I was still guessing it was Charlize Theron (POTUS) They did some incredible subtle CGI or something Undetectable, what ever it was to really draw you into her character and striking beauty Tricks; like one moment she's glamorous, hot and funny etc,.. then Like this blank canvas, I thought maybe Ms. Theron's younger sister or look alike, the girl next door, farmer John's daughter,.. I don't know No words as it was some trick.