I need a person cut out, pasted into another image and edited to look natural

I have two images. One of my class mate in her prom dress, and the second of my class at prom. My classmate in the first image didn't make it to the class photo and has asked to be photo shopped into the background between two girls (only her not her and her partner). (I'm going to send in three images in total. Two for you to work with, and one to show you where she would like placed into the image). She would also like some basic lighting and shadow editing so that she can fit in naturally with everyone else in the photo.

Thank you very much,

Benjamin Robinson