Buffy...hmm, how about Angel? 
In my head I have now put poor Molly Weasley in Body Shop White Musk and sent her to the Ministry of Magic office Christmas party where she encounters a perfectly groomed Narcissa wafting a cloud of one of the Chanel Les Exclusifs. Whereupon Narcissa wrinkles her patrician nose and murmurs: "White Musk - I haven't smelt that since I left the Slytherin dormitories." And with her it most certainly isn't foot in mouth syndrome.
Professor Sprout I've given my SOTD - Vent Vert - to go with the greenhouses, Professor Trelawney gets L' Air de Rien or something very patchouli-heavy, Professor McGonagall, Je Reviens, Harry's mother, L' Air du Temps and Anais Anais - the poor woman deserves something nice to make up for her impending doom and prat of a husband.
Professor Umbridge did have a revoltingly girly side to her. Think of the bows and the fluffy kitten plates. So I can see her going for something aimed at teenagers. How about Aquolina Pink Sugar?
James Potter is the type to drown himself in Lynx and wait expectantly for females to find him irresistible. Sirius would probably pick something very classy and expensive, a Tom Ford of some kind maybe.
But what about Aunt Petunia? It's got to be something expensive, conservative and brag-worthy. Chanel maybe?