I found the anime version of Fred and George!!

Kaoru is the George

Hikaru is the Fred

I know nobody cares, but I like to sort people in Hogwarts houses when I see them

Hmm... Hikaru and Kaoru in Gryffindor

Kyoya (left with glasses) is a Ravenclaw

Honey (bottom left) in Hufflepuff

Tamaki (second right) is definitely a Hufflepuff

Mori (tallest right)... hmm... looks like a Slytherin... but... he's very loyal, and would probably be in the same house as Honey... so Hufflepuff as well

And last, Haruhi (bottom right), she would be... if I'd look at her class, it would be logic to be in Gryffindor, with the twins, but her personality is more a Ravenclaw, so I guess Ravenclaw

Honey and Mori are in the highest grade

Tamaki and Kyoya are one grade younger

And Haruhi, Hikaru and Kaoru are the youngest