Howdy there! I'm Whit, and I play six (HOLY CRAP) characters here. :)
vivalaviv: is Vivian Diggory, aka Cedric's Mum. She works at the Ministry, is regarded as a pretty by-the-books Pureblood, and tends to be nice to eeeeveryone. She does loathe purists and Death Eaters, but her default setting is polite, so there's that.
dutifulson: is Barty Crouch Jr., and he's living his double life of perfect crime-fighting Ministry sycophant by day, bloodthirsty Death Eater by night. He's got serious issues, to say the least, and Rodolphus would be aware of his double life. After reading your Rodolphus app, Bary would likely worship the ground he walks on. Barty's not really caring about the blood purity - really, he's just psychotic and likes killing people - BUT he does admire the man's steady methods.
sparethenheir: is Regulus Black, and he's not NEARLY as happy a Death Eater as Barty is. He's actually started research on the Horcruxes, and while the idea of ~betrayal~ hasn't quite hit his little skull yet, the seed is germinating. Regulus, to all outside perceptions, is the perfect heir that Sirius never was, and is respectful toward Purebloods and derisive to anything less. He has pretty much... no self-esteem at all, so he'd try his hardest to be likable to Rodolphus and thrives off of praise. So... there's that.
nickatnight: is my Muggle vampire who's a little over 400 years old. Nick Harrow is an extremely non-broody, laidback person who campaigns for vampire rights. He's hard to rile up one way or another and makes an effort to educate those that dislike vampires. He's unafraid of bigots or of purists, and will totally attempt to start dialogues with them. So that could be an interesting dynamic.
kissoff: is Doris Purkiss, who's a shallow, loudmouth, girly Hufflepuff in James Potter's year. She's silly and sassy, and tends to play dumb, but she's also got a big mouth and doesn't know when to shut up. She'd probably (stupidly) sass Rodolphus if she heard him say anything too overtly purist. While secretly thinking him hot. Sigh.
And we already discussed Sturgis, so there ya go! <33 Welcome to the game!!