wow....look very young, like 16-17?

btw....picture is too small

first picture looks like she's having stomach ache

#5 - if me i would prefer to fill the frame and leave a little room on top

that way you can show more of her dress, you dont always need to be close up

#2 if me i would pose her hand backward holding the dress and shot in landscape at eye level, put her at the left side of the frame and right side of the frame show her white dress, if is in portrait then fill the frame like what i said in #5

actually is a matter of personal matter and client preference, that's what i will do if i'm shooting her