Unlike most of you, I don't see Cass as Gryffindor. Hufflepuff might be closer imo, aside from her sense of humor (or lack thereof...)
I'll go with:
Gryffindor: Bravery, Daring, Nerve, and Chivalry
DA:I: Alistair, Cullen, Dorian, Sera (The whole robinhood thing sounds like gryffindor to me), and The Iron Bull (losing his eye defending Krem)
Others: Wynne, Bethany, Aveline, Anders
Hufflepuff: Hard work, Patience, Loyalty, Fair Play
DA:I Josephine, Cassandra (works hard, loyal), Cole
Others: Sten, Oghren
Ravenclaw: Intelligence, Knowledge, Wit
DA:I: Solas, Blackwall,
Others: Shale, Fenris
Slytherin: Ambition, Cunning, Resourcefulness
DA:I: Vivienne, Morrigan, Varric (fits the bill, he's just not an a-hole)
Others: Zevran, Isabela, Loghain, Flemeth, Merrill