Here's a thing cuz my friend and I are obsessing over a Hogwarts AU with the Super 6... finally got her into it mwahaha I didn't used to be so into this au because everyone's already done everything you possibly can with it....BUT IT'S FUN
I don't think Elsa is Slytherin. I think she's Hufflepuff, because she really didn't show much personality in the movie but at least she showed love for his sister to last, or something like that. I think you guys put her in Slytherin because you're thinking about Jack, but no, she's not Slytherin; you know what?, Elsa and Anna are from beauxbatons XD And Moreover, Astrid is a Slytherin, she is sooo ambitious and intelligent, crafty, she's a strong leader, and achievement-oriented, she's soo Slytherin XD And Bunny... Well, I don't know where he can go XD
i'm definitely not thinking about jack when i think about elsa. i'm thinking about elsa when i think about elsa. they're not the same person. to me, she's a slytherin. astrid is way too brash and headstrong to be a slytherin, while elsa is more dignified about her strength and considers her powers before using them (at least, now she does). astrid isn't that cunning, she even said she's more of a "lop its head off and ask questions later" kind of person. elsa tried diplomacy first while being attacked, and only resorted to violence later, using her anger as fuel. slytherins use their words and only physically fight when personally offended.
Actually what she did was panic which led to, well, what we saw in the movie. Is aware of his powers, and I do not know how she is sure of herself when she was locked up all this time, you know, scared of his powers and stuff. Astrid is very stubborn, but the truth is she's very ambitious, enough to want to be the best in the class no matter what. And that's what makes a Slytherin.