Nyan isn't really trolling. She realizes how big of a moment it is for Takamina's grad to coincide with the 10th anniversary. so she's waiting until that heat dies down so that it's not too much all at once. Plus, wouldn't it be weird to Nyan and Mina to graduate without Miichan? With Mina going first, it shows that they're looking to go their separate ways. Nyan is definitely next, though. I think Mii's captain status will keep her around for a while. Then again, I thought the same of Mocchi, and I was very wrong. As for next to grad after Nyan... I think 2nd gen's days are numbered. Sae and Umeda have a bit of fresh air now with their SKE/NMB gigs, but Kana is rotting in oblivion.