Fat Amy and Blake
Blake seemed like he would be a good roommate, and she trusted his judgment when he vouched for Castiel. No, she didn't know the angel, but that was perfectly alright. She hadn't known Caroline very well when they had become roommates, and that had worked out quite well.
"It definitely will be fun," she said with a smile. "There are two bedrooms that aren't being used, so you and Castiel can choose whichever one you want." She didn't know if angels slept or not. She assumed they'd want to share a room, though, as Blake said Cas was his boyfriend.