No.6 Discussion Board

I'm not so sure about that Nezumi and Slytherin thing. Sure he was the best at many things but it was because he had to learn them to survive in such environment that was West Block and rest on NO.6 hell. As kid he wanted to travel and sing. As older he often spend his free time with books that he love.
Both he and Shion are smart to remember so many lines from so many books. Nezumi is really smart but he give feeling like, if he gone to school, he wouldn't care for grades and slack off. So Ravenclaw wouldn't be so bad idea.

If he meet with Shion before school he might just wanted to go to that house because Shion was choosed there.
Little Nezumi could meet Shion year or more before after his parents got killed, the might been wizards, and Shion helped and feed him him. Karan can be mugole. Both of them let Nezumi stay in their house but Nezumi disappear after few dats because he didn't want them be mixed in danger things from wizard world. No one yet know that Shion have power too.
they meet again in first day of school at Hogward.
At ceremony Shion was first choose into Ravenclaw and Nazumi when put hat on his head wanted to be with Shion there and that happened.
With time everyone were wondering why Nezumi is there if he such lazy parson (for Ravenclaw level) when in comes to study (still he get middle good grades). He won't tell about it even Shion until a lot later when they 16 and starting to realize they have deeper feelings for each other.       

Safu better fit Sytherin because she always thought about herself first then others (that's feeling I got about her since that scene when she say she don't care what Shion would wanted, she going to do what she wants).