So my internet is currently down but I don't feel like waiting hours to do this, so I'm posting from my phone instead :D
I went through waay too many PB possibilities for Vlad. First was Gary Oldman, then Richard Armitage, then some other dude... until I thought about evil characters and then I was like "OMG VOLDEMORT." Then I settled on Ralph Fiennes and he was perfect. :D
For Cole I seriously considered using David Tennant, but I was afraid that I'd end up making him too much like the Doctor so I went searching through pb_updates and found Justin Theroux instead, who looked like he could fit the whole jumpy teacher look.
Hannah was easy. I've always wanted to use Billie Piper as a PB and she fit the character perfectly.
Bran was a little harder. I needed someone who looked intimidating with a potential to be crazy thrown in. I considered Clive Owen for a second but Christian Bale was pretty much my only main choice. The American Psycho icons I found sealed the deal XD
Aand Sarah, even though I need to start doing more with her. >__> Natalie Portman was my first choice and I stuck with her because she has that 'girl next door' look and I think she's pretty without being fake or overdone.