Been a while since I read any Harry Potter, but I'm guessing the bunny girl is Luna Lovegood. But then who is the lion-haired one?
Not sure if I get the joke here. Is Lelouch the Half-blood Prince referred to here, because his mother wasn't a noble? And is Hermione slapping Harry for chumming up with a Slytherin (Lulu's green and yellow cape)?

I beleive you have hitten the nail on the mark.

Actually, this is Tom Riddle cosplaying as Lulu. This is because the first sentence of the speech bubble says "Tom Morv--(cut off) commands you!" It's been a while since I read Half-Blood Prince myself, so I can't say who the bunny girl is...though, if I -had- to take a stab at it, I would say Bellatrix Lestrange just because she's obsessed. I'm not entirely sure, though.

eh, luna is the one with the lion hat thing i'm pretty sure.

Anime Luna...
HNNNNNNNGGGGGGGGGGGGGGGGGGGGGG!!!!!~!@$ashg

Somebody should just fund it for an anime production~! <3

Top right side - Hermoine didn't like that idea at all. She's already scrapped it.

Oh Luna.