Per wiki policy, Spoilers Off applies here and all spoilers are unmarked. You Have Been Warned.
Sorata and Nanammi were already "different" before they came to Sakurasou
Both of them adjust fairly quickly to the very unconventional habits of the people living there, eventually getting to the point of taking the other resident's latest wacky shenanigans in stride and even keeping up them. By the time the second year rolls around, both him and Nanami are fully capable of freaking out the new kids as effectively as they were by the seniors. Sorata is obviously bored being "normal" and Nanami at times borders on an almost obsessive level of dedication to her ambitions and goals