I was killing before killing was cool.

Nelle Longbottom
Model: Emily Browning
 
She's lovely, and so is Neville.
I think she's pretty but maybe isn't really noticed like more of a normal beautiful and not film star beautiful and hot idk.

Hermes John Granger
Model: David Tennant (younger)
 
I have to thank this one to @driftwood13
Well, he doesn't has Hermione's hair.
He's just perfect for the clever roles. In takin' over the asylum and Doctor Who he plays really different characters but they're always clever.
And well, who doesn't love David? He's just amazing.
And look Baby Tennant, he's too cute.

Dracy Lucie Malfoy
Model: Taylor Momsen
 
The hair is just perfect (it seems like I'm choosing the characters by the hair).
She has like this dark appearance perfect for Draco.

Ronette Billie Weasley
Model: Karen Gillan
 
She's so funny just as Ron.
She's so beautiful, how could Hermes not fall in love with her?

Harriett Jane Potter
Model: Daisy Lowe
 
She would totally have Harry's messy hair.
She would dress with baggy clothes as they are second hand of her cousin Dudley (I don't know what his name would be like for girl)
She would start to dress sexier on the last years with skirts but still wearing the big hoodies