[judasmartel]

Spoiler for Theories:

1. Kazuki Fujisawa (the game developer whose work was the inspiration for Sorata's first game) was either a former resident of Sakurasou who may or may not have got out of SS or may have later on led a successful career, if not a normal life; or at least knew about Sakurasou. In either case, there's another theory that both he and Chihiro-sensei knew of each other.

If Episode 8 of the anime is to be believed, Fujisawa-sensei is actually quite surprised to see a Suiko student making it to the first round of the game making contest where he was one of the judges. Since making games at that level is something usually associated with the people of Sakurasou (strange and quirky but GODLY in what they do), one could say that either he assumes Sorata was a Sakurasou resident or simply that there must be something so special about him that piqued his interest.

2. Yuuko-chan will become a Sakurasou resident herself, but only if she develops a Sakurasou-level talent in something. From her (as of date) only appearance, her talent is apparently in singing, so she has the potential to become Suiko's resident Idol Singer if she managed to get in there. It does help that she gets along with the current Sakurasou tenants pretty well.

But unlike her brother Sorata, who took his new status as a Sakurasou resident pretty badly at first, she would be very proud of it despite the stigma attached to the status because she found that the Sakurasou residents are actually really great people.

However, by the next year (when Yuuko now becomes a high school student herself), Jin and Misaki are out (since they will have already graduated), so she's left with Sorata, Mashiro (if she never leaves for England), Dragon (b/c Ryuunosuke is quite long), and Nanami (though Yuuko dislikes her).

Nonetheless, given her energy, she's good enough to be Misaki 2.0.