I think Aral has to be a Gryffindor, in the end. He WANTS to be honourable and straightforward all the time, and it just sucks for him that his life isn't going to let that be an option; that's why he keeps trying to drink himself to death. Piotr, though, was a very natural Slytherin (unless he's another ruthless Hufflepuff: twenty years of guerrilla warfare suggests an impressive capacity for hard work and persistence in the face of overwhelming odds).

Illyan is a Muggle, tasked with looking after and herding all these mad wizards.