I'm going to spoil very much of the game here, so be careful if you really want to read the the parts that are locked.
I know that Emma's story pisses a lot of players. Why did she had to cut her hair, why did she changed her boobs, why the lips.
Up till this moment, in my opinion Emma is the best written character. She's the main girlfriend, but she noticed things about the MC. Beside Tris and Charlotte she knows the MC best. She noticed how our MC looked at Tris and Charlotte all this time. At first she thought, oh he just has a very good relationship with his mom/sister, but then there were times when she noticed that as a son/brother you were not supposed to get hot over your mother/sister, so what she's trying is to be more like them. That's why she cut her hair, to look more like Tris/Charlotte.
Then the boobs, she feels like she's loosing the MC and she taught that making her boobs bigger, might prevent that.
The lips: it's not in the story yet, but she did her lips way before episode1. I will cover this part in an upcoming episode.
As for your "long hair" part, it can't be done, at least not yet. Once she'll get past her insecurities she'll let her hair grow, but the hair can't grow up in two versions, best case scenario, she'll have a longer hair in season 3.
Then let's talk about the anal part. She was not very sure she would want to do that, but maybe this way he would never leave her. She gives him everything he wants, right? And if he would have any other fantasies, she would do it as long he's hers.
She's a bit unstable, just like a 18 years old, who thinks she could never find love again.