Aeri would choose--a hot girl. He needs to meet Caroline.
Ava would choose Castiel or Venom--just to mess with Castiel and Venom because she thinks she could live with him and not want to snap his neck.
Alma would choose Kanda, of course. For lots of various reasons, like the fact he believes they're destined to be together and other creepier ones.
Itachi would choose...no one. He REFUSES. He'd end up picking Jun or Sakura if he absolutely had to pick someone.
Johnny's choice is obvious. And he'll even let Cherry be the husband! XD
Josak wouldn't pick anyone and all the closest people to him are big fat NOs so Acumen could do random selection here.
Miranda would stutter and stumble and have no idea what to do because SHE CAN'T MARRY ANYONE LIKE THIS. But if someone asked her? She's probably agree to it to get the embarrassment out of the way. Or she'd pick Lenalee so she could protect her honor from all the guys. :|