Although I’ve heard of most of these. I never heard that buttoning in order or putting one’s hand behind one’s back is problematic (although I think I saw somewhere that there’s an inyan al pi kabbalah not to put on’s hands below one’s waist).
As for cutting nails on Thursday, the Mishnah Berurah holds that the only problem is that one is not mekayaim kavod Shabbos, as SSD said. However, the Elyah Rabbah holds that there is a real Halachic problem with doing this, since it is causing one’s nails to grow on Shabbos.